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Plastics Engineers (plastic + engineer)
Selected AbstractsReactive extrusion of poly(ethylene terephthalate),(ethylene/methyl acrylate/glycidyl methacrylate),organoclay nanocompositesPOLYMER COMPOSITES, Issue 2 2007Elif Alyamac This study was conducted to investigate the effects of component concentrations and addition order of the components on the final properties of ternary nanocomposites composed of poly(ethylene terephthalate), organoclay, and an ethylene,methyl acrylate,glycidyl methacrylate (E-MA-GMA) terpolymer acting as an impact modifier for PET. In this context, first, the optimum amount of the impact modifier was determined by melt compounding binary PET-terpolymer blends in a corotating twin-screw extruder. The amount of the impact modifier (5 wt%) resulting in the highest Young's modulus and moderate elongation at break was selected owing to its balanced mechanical properties. Thereafter, by using 5 wt% terpolymer content, the effects of organically modified clay concentration and addition order of the components on the properties of ternary nanocomposites were systematically investigated. Mechanical testing revealed that different addition orders of the materials significantly affected the mechanical properties. Among the investigated addition orders, the best sequence of component addition (PI-C) was the one in which poly(ethylene terephthalate) was first compounded with E-MA-GMA. Later, this mixture was compounded with the organoclay in the subsequent run. In X-ray diffraction analysis, extensive layer separation associated with delamination of the original clay structure occurred in PI-C and CI-P (Clay + Impact Modifier followed by PET) sequences with both 1 and 3 wt% clay contents. X-ray diffraction patterns showed that at these conditions exfoliated structures resulted as indicated by the disappearance of any peaks due to the diffraction within the consecutive clay layers. POLYM. COMPOS., 28:251,258, 2007. © Society of Plastic Engineers [source] Mechanical properties of injection molded long fiber polypropylene composites, Part 1: Tensile and flexural propertiesPOLYMER COMPOSITES, Issue 2 2007K. Senthil Kumar Innovative polymers and composites are broadening the range of applications and commercial production of thermoplastics. Long fiber-reinforced thermoplastics have received much attention due to their processability by conventional technologies. This study describes the development of long fiber reinforced polypropylene (LFPP) composites and the effect of fiber length and compatibilizer content on their mechanical properties. LFPP pellets of different sizes were prepared by extrusion process using a specially designed radial impregnation die and these pellets were injection molded to develop LFPP composites. Maleic-anhydride grafted polypropylene (MA- g -PP) was chosen as a compatibilizer and its content was optimized by determining the interfacial properties through fiber pullout test. Critical fiber length was calculated using interfacial shear strength. Fiber length distributions were analyzed using profile projector and image analyzer software system. Fiber aspect ratio of more than 100 was achieved after injection molding. The results of the tensile and flexural properties of injection molded long glass fiber reinforced polypropylene with a glass fiber volume fraction of 0.18 are presented. It was found that the differences in pellet sizes improve the mechanical properties by 3,8%. Efforts are made to theoretically predict the tensile strength and modulus using the Kelly-Tyson and Halpin-Tsai model, respectively. POLYM. COMPOS., 28:259,266, 2007. © 2007 Society of Plastic Engineers [source] Effects of alkali and silane treatment on the mechanical properties of jute-fiber-reinforced recycled polypropylene compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2010Xinxin Wang Jute-fibers-reinforced thermoplastic composites are widely used in the automobile, packaging, and electronic industries because of their various advantages such as low cost, ease of recycling, and biodegradability. However, the applications of these kinds of composites are limited because of their unsatisfactory mechanical properties, which are caused by the poor interfacial compatibility between jute fibers and the thermoplastic matrix. In this work, four methods, including (i) alkali treatment, (ii) alkali and silane treatment, (iii) alkali and (maleic anhydride)-polypropylene (MAPP) treatment, and (iv) alkali, silane, and MAPP treatment (ASMT) were used to treat jute fibers and improve the interfacial adhesion of jute-fiber-reinforced recycled polypropylene composites (JRPCS). The mechanical properties and impact fracture surfaces of the composites were observed, and their fracture mechanism was analyzed. The results showed that ASMT composites possessed the optimum comprehensive mechanical properties. When the weight fraction of jute fibers was 15%, the tensile strength and impact toughness were increased by 46 and 36%, respectively, compared to those of untreated composites. The strongest interfacial adhesion between jute fibers and recycled polypropylene was obtained for ASMT composites. The fracture styles of this kind of composite included fiber breakage, fiber pull-out, and interfacial debonding. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers. [source] Fabrication and properties of nano-ZnO/glass-fiber-reinforced polypropylene compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2010Yi-Hua Cui Polypropylene (PP) is widely used in many fields, such as automobiles, medical devices, office equipment, pipe, and architecture. However, its high brittle transformation temperature, low mechanical strength, dyeing properties, antistatic properties, and poor impact resistance, considerably limit its further applications. Nano-ZnO treated by KH550 coupling agent and glass fibers (GFs) were introduced in order to improve the mechanical performance and flowability of PP in this research. The crystallization behavior and microstructure of nano-ZnO/GFs/PP hybrid composites were analyzed by differential scanning calorimetry, transmission electron microscopy, and scanning electron microscopy. The effect of crystallization behavior on the mechanical properties of the nanocomposites was investigated and analyzed. The results indicated that nano-ZnO surface-coupled by KH550 could be uniformly dispersed in the PP matrix. The incorporation of nano-ZnO and GFs resulted in increases of the crystallization temperature and crystallization rate of PP and a decrease of the crystallization degree. The introduction of nano-ZnO and GFs also enhanced the tensile strength and impact toughness of the hybrid composites and improved their fluidity. Composites containing 2% of nano-ZnO and 40% of GFs possessed the optimum mechanical properties. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Correlation of morphology, rheology, and performance improvement in gasoline tubes based on PA-6 nanocompositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2010Mehdi Moghri PA-6/organo-modified layered silicate nanocompounds were prepared by the melt mixing of PA-6 with different nanoclay loadings in a corotating twin-screw extruder. Gasoline tubes based on these nanocompounds were produced at different silicate loadings. Thermal, mechanical, rheological, and barrier properties of the different samples were investigated and correlated to their morphology. Transmission electron microscopy, wide angle X-ray scattering, and linear melt state viscoelastic measurements were used to characterize the different aspects of nanoclay dispersion in the nanocomposite samples. While tensile modulus, softening point, heat distortion temperature, and gasoline barrier properties of the prepared tubes were improved considerably by increasing the clay content, performance improvement with respect to clay content (after a certain value) decreased with increasing clay loading. It could be attributed to the re-agglomeration of tactoids at higher concentrations. These findings were correlated with the rheological and morphological observations. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Properties and morphology of poly(vinyl chloride) blends with solid-state-chlorinated polyethyleneJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2010Yuhong Zhang Correlations of the stress-strain behavior and impact strength of poly(vinyl chloride) (PVC) blends with different amounts and chlorine contents of solid-state-chlorinated polyethylene (CPE) were studied. The relationships between the morphology and properties of the PVC/CPE blends also were investigated. The results of dynamic mechanical analysis and transmission electron microscopy showed that PVC/CPE blends are partially compatible systems and that a certain interaction exists between the two phases. When the amount of CPE (chlorine content, 36,42%) was 7,15 phr (parts by weight per hundred parts of resin), an essentially perfect CPE network was formed, and the blends showed better impact resistance. A Brabender Plasticorder study revealed that CPE can promote the plasticity of PVC and improve its processability. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Morphological, mechanical, and rheological studies of PVC/ABS blends in the presence of maleic anhydrideJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2010Pegah Mohammad Hosseinpour A novel method of enhancing compatibility in PVC/ABS blends is the use of ABS-grafted-(maleic anhydride) (ABS- g -MAH) as a compatibilizer. In this study, maleic anhydride was grafted onto ABS (initiated by peroxide) in an internal mixer. Grafting degree was determined by a back-titration method, and certain amounts of the resultant ABS- g -MAH were added to PVC/ABS blends during their melt blending in the mixer. The weight ratio of PVC to ABS was kept at 70:30. Evaluation of compatibilization was accomplished via tensile and notched Izod impact tests, scanning electron microscopy (SEM), and rheological studies. According to the SEM micrographs, better dispersion of the rubber phase and its finer size in properly compatibilized blends were indications of better compatibility. Besides, in the presence of a proper amount [5 parts per hundred parts of PVC (php)] of ABS- g -MAH, PVC/ABS blends showed significantly higher impact strengths than uncompatibilized blends. This result, in turn, would be an indication of better compatibility. In the presence of 5 php of compatibilizer, the higher complex viscosity and storage modulus, as well as a lower loss modulus and loss factor in the range of frequency studied, indicated stronger interfacial adhesion as a result of interaction between maleic anhydride and the PVC-SAN matrix. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Comparative study of the effects of chlorinated polyethylene and acrylic impact modifier on the thermal degradation of poly(vinyl chloride) compounds and poly(vinyl chloride)/(oil palm empty fruit bunch) compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2010Aznizam Abu Bakar The effects of chlorinated polyethylene (CPE) and acrylic impact modifier (AIM) on the thermal degradation of poly(vinyl chloride) (PVC) compounds and composites were investigated. The amounts of AIM and CPE used were fixed at 9 parts per hundred parts of resin (phr), while oil palm empty fruit bunch (OPEFB) fiber content was increased from 0 to 40 phr. To produce composites, the PVC formulations were dry-blended by using a laboratory blender before being milled into sheets on a two-roll mill at 165°C. The milled sheets were then hot-pressed at 180°C. The thermal degradation of the specimens was evaluated by using thermogravimetry in a nitrogen environment. Thermal stability of the PVC/CPE compounds and PVC/CPE/OPEFB composites was improved by the addition of CPE. The CPE retarded the dehydrochlorination of PVC. However, the stabilization effect was reduced by the incorporation of OPEFB at levels of 30 and 40 phr. The presence of AIM accelerated the dehydrochlorination of PVC/AIM compounds and PVC/AIM/OPEFB composites. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Effect of cyanoguanidine-metal and urea-metal complexes on the thermal degradation of poly(vinyl chloride)JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2010Abir S. Abdel-Naby Tin, nickel, cobalt, zinc, and copper complexes of cyanoguanidine and urea were synthesized and investigated as thermal stabilizers for rigid poly(vinyl chloride) at 180°C in air. Their stabilizing efficiencies were evaluated by measuring the induction period (the period during which no evolved hydrogen chloride could be detected) and the rate of dehydrochlorination as determined by continuous potentiometric measurements, in addition to the extent of discoloration. The results clearly revealed the greater efficiency of all of the investigated metal complexes as compared to those of well-recognized reference stabilizers. The tin complex always exhibited the highest efficiency irrespective of the type of ligand used. The nickel and cobalt complexes also possessed high stabilizing efficiencies. The order of the stabilizing potency of the various metal complexes was Sn , Co, Ni , Zn, Cu. Combining the ligand itself with dimethyltin- s,s,-bis (isooctyl thioglycolate), as a reference stabilizer containing a tin atom, led to a true synergism. This synergistic effect might be attributed to the formation in situ of a complex between the ligand and the tin atom. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Effect of the combination of a benzophenone-type ultraviolet absorber with thermal stabilizers on the photodegradation of poly(vinyl chloride)JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2010Xiuqin Xiang The effect of the combination of a UV absorber (Chimassorb 81) with different types of thermal stabilizers, including an organic calcium complex and an organotin mercaptide, on the photodegradation of poly(vinyl chloride) (PVC) was investigated by color difference measurements, UV,Vis spectroscopy, Fourier-transform infrared spectroscopy, thermogravimetric (TG) analysis, and viscosity-average molecular weight determination. Films of PVC containing 0.5 phr of Chimassorb 81, with and without 2 phr of a thermal stabilizer, were prepared by solution casting. Then the accelerated UV weathering of the films was carried out under xenon light with an irradiance of 0.51 W/(m2 · nm) at 65°C. The results showed that both Chimassorb 81 and the mixture of Chimassorb 81 with the organic calcium complex showed good behavior in inhibiting the photodehydrochlorination and photooxidation of PVC. In contrast, the combination of Chimassorb 81 and methyltin mercaptide significantly accelerated initial color development during the final 200 h of exposure because of the UV sensitivity of the organotin. Moreover, when Chimassorb 81 and the methyltin mercaptide were used together to stabilize PVC films, the expected antioxidant effect of the mixture was not observed, in contrast to the behavior found with other stabilized systems, perhaps because the Chimassorb 81 had been depleted by the methyltin mercaptide during the UV irradiation. The TG analysis revealed that ultraviolet irradiation had caused severe destruction of the PVC chains. However, addition of Chimassorb 81 or the combination of Chimassorb 81 with the organic calcium complex effectively prevented the destruction, as was demonstrated by changes in the activation energies for thermal degradation. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Mechanical properties of particulate-filler/woven-glass-fabric-filled vinyl ester compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2010L. Yusriah Studies of the effect of particulate fillers on specific mechanical properties of vinyl ester epoxy (VE) reinforced with woven glass fiber composites were carried out with different filler types and particulate filler contents (1%, 3%, and 5% by weight). Two types of particulate filler were used, i.e., calcium carbonate (CC) and phenolic hollow microspheres (PHMS). The composites were prepared by using a hand lay-up and vacuum bagging method. Woven glass fabric composites filled with particulate PHMS were observed to have better specific flexural strength and specific impact strength, as well as lower density, than those filled with particulate CC. Morphological features determined by scanning electron microscope (SEM) proved that the PHMS filler experienced good bonding in the VE matrix, a feature which contributed to the improvement in the properties of the composites. The incorporation of particulate fillers into the composites also influenced the storage modulus with a minimal effect on Tg. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Preparation and characterization of polyaniline-DBSNa/Fe2O3 and polyaniline-DBSNa/CoO nanocomposites using surfactive dopant sodium dodecylbenzenesulfonate (DBSNa)JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2010Hossein Eisazadeh Nanocomposites of polyaniline (PAn) containing nanometer-size Fe2O3 and CoO were synthesized by a chemical method using sodium dodecylbenzenesulfonate (DBSNa) as a surfactant. Characteristics of the products such as morphology, particle size, and conductivity were studied. The results indicated that these properties were dependent on the surfactant and the type and content of metallic oxide used. When the concentration of Fe2O3 and CoO increased from 1 to 5 g/L in the PAn-DBSNa/Fe2O3 and PAn-DBSNa/CoO composites, the conductivity decreased from 1.3 × 10,4 to 5.1 × 10,5 and from 1.4 × 10,4 to 5.1 × 10,5 S/cm, respectively, while the particle size increased from 92 to 103 and from 104 to 117 nm, respectively. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] A brief overview of theories of PVC plasticization and methods used to evaluate PVC-plasticizer interaction,JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2009Paul H. Daniels This paper reviews the most widely used models for explaining how plasticizers render PVC flexible. These models include the gel, lubricity, and free volume theories; kinetic theories; and mathematical models which predict on the basis of plasticizer structure how much a plasticizer will lower the polymer glass transition in a flexible PVC compound. Since plasticization results from interactions between plasticizer and polymer, methods which have been used to study either the strength or the permanence (or both) of those interactions are also briefly discussed. Tools which have often been used to study plasticizer-PVC interactions include infrared and nuclear magnetic resonance spectroscopy, compression and humid-aging tests, dynamic mechanical analysis, torque rheometer tests, plasticizer-resin clear point temperature measurements, plastisol gelation/fusion by hot stage measurements, and others. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] Photostabilizing effect of some thermal stabilizers for poly(vinyl chloride) in the presence of fillerJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2009D. Braun The commercial stabilizers Ca-Zn stearate and dibutyltin- S,S,-di(isooctyl thioglycolate) have been investigated as photostabilizers for rigid poly(vinyl chloride) (PVC) in the presence of two types of CaCO3 as filler (natural and modified). The results reveal the costabilizing efficiency of CaCO3, especially the natural type, when it is used in concentrations of 1,30% by weight. The stabilizing efficiency of CaCO3 is indicated by the longer induction period and the lower rate of dehydrochlorination. The stabilizing effect of CaCO3 may be attributed because of its opacity and action as a screening agent by reflecting ultraviolet light, thereby hindering the penetration of the light into the polymer matrix. In addition, CaCO3 has the ability to absorb the HCl evolved during processing. The slight difference in the stabilizing effect of natural CaCO3 compared to that of the modified one can be attributed to the modification process, that may decrease the number of active sites on the surface of CaCO3, that in turn are responsible for the absorption of the evolved HCl. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] Modification of waterproofing asphalt by PVC packaging wasteJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2009Changqing Fang Recycled packaging waste poly(vinyl chloride), instead of an ordinary polymer modifier, was adopted for the modification of an asphalt waterproofing membrane. The physical performance of the membrane was studied. Results showed that the softening point of the modified asphalt was increased, while the penetration degree was reduced. Also, under natural aging conditions, the tension, the retention of extension under the greatest tension, and the retention of low-temperature flexibility were all improved significantly. At the same time, the resistance to acid, alkali, and salt corrosion of the modified waterproofing membrane was improved. The mechanism of the modification was studied by Fourier transform infrared spectroscopy and microstructure analysis. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] Processability and mechanical properties of commercial PVC plastisols containing low-environmental-impact plasticizersJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2009Paola Persico Preliminary results are presented concerning the use of less-toxic plasticizers such as dioctyl adipate (DOA) and acetyl tributyl citrate (ATBC) in plastisol formulations for rotational molding technology. The DOA and ATBC plasticizers have been studied by comparing the effects of their content, molecular architecture, and polarity on the rheological behavior of liquid plastic systems and on the mechanical properties of the ultimate products prepared with PVCs having different particle sizes and molecular-weight distributions. Rheological tests have confirmed the differences in solvent power of the diethylhexyl phthalate (DOP), DOA, and ATBC plasticizers. The glass transition temperatures measured on rotomolded samples have shown that the use of ATBC leads to a more nearly rigid system as a consequence of the branched structure and polarity of this plasticizer when compared with DOA. Mechanical tests carried out on final products after natural and forced environmental aging revealed a slight decrease in their performance. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] Rigid PVC/(layered silicate) nanocomposites produced through a novel melt-blending approach,JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2009Laurent M. Matuana On the basis of the fusion behavior of poly(vinyl chloride) (PVC), the influence of compounding route on the properties of PVC/(layered silicate) nanocomposites was studied. Four different compounding addition sequences were examined during the melt compounding of PVC with montmorillonite (MMT) clay, including (a) a direct dry mixing of PVC and nanoclay, (b) an addition of nanoclay at compaction, (c) an addition of nanoclay at the onset of fusion, and (d) an addition of nanoclay at equilibrium torque. Both unmodified sodium montmorillonite (Na+ -MMT) and organically modified montmorillonite (Org.-MMT) clays were used, and the effect of the addition sequence of the clay during compounding on its dispersion in the matrix was evaluated by X-ray diffraction and transmission electron miscroscopy. The surface color change, dynamic mechanical analysis, and flexural and tensile properties of PVC/clay nanocomposites were also studied. The experimental results indicated that both the extent of property improvement and the dispersion of nanoparticles in PVC/(layered silicate) nanocomposites are strongly influenced by the degree of gelation achieved in PVC compounds during processing. The addition of nanoclay to PVC must be accomplished at the onset of fusion, when PVC particles are reduced in size, in order to produce nanocomposites with better nanodispersion and enhanced mechanical properties. Overall, rigid PVC nanocomposites with unmodified clay (Na+ -MMT) were more thermally stable and exhibited better mechanical properties than their counterparts with organically modified clay (Org.-MMT). J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] Metal-exchanged clay and zeolite additives as smoke suppressants and fire retardants for poly(vinyl chloride)JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2009Alexander G. Zestos Cone calorimetry studies showed that various metal-exchanged clays and zeolites containing only 3,4% of Cu(II), Cu(I), Zn(II), or Al(III) were effective smoke suppressants and fire retardants for plasticized poly(vinyl chloride). Copper(II)-Zn(II) and Cu(II)-Al(III) synergism for smoke and heat reduction was observed with binary blends of the clays, and the effectiveness of the additives was usually improved considerably by heating plasticizer-additive mixtures under very high shear before combining them with the polymer. Possible mechanisms of action of the additives are described. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] Color inhibition of phenolic antioxidants in Ziegler-Natta polyethylene.JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2009Although the level of transition-metal catalyst residues in polyethylene (PE) has been drastically reduced over the years, they can still give rise to discoloration, particularly when associated with other additives such as antioxidants. This first of this series of papers screens a variety of candidate color suppressants featuring a range of functional groups, including alcohols, amine/sulfur compounds, and acid-containing species. These candidate color suppressants were melt-blended into a Ziegler-Natta linear low-density PE in combination with 2,2,-isobutylidenebis(4,6-dimethylphenol) (a highly discoloring hindered bisphenol antioxidant) and zinc stearate antacid. Yellowness index measurements made after multiple extruder passes indicated that dipentaerythritol (DPE) and triisopropylamine (TIPA) gave good color inhibition and, in some cases, outperformed established phosphites. The DPE and TIPA were found (via melt flow rate measurement) not to affect melt stability, and hydroperoxide determination revealed that DPE had no peroxide decomposition activity. The latter results indicate that the color-suppression mechanism of DPE and TIPA is different from that associated with phosphites. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] Effect of single-mineral filler and hybrid-mineral filler additives on the properties of polypropylene compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2009A.K. Nurdina The present study was carried out to determine the filler characteristics and to investigate the effects of three types of mineral fillers (CaCO3, silica, and mica) and filler loadings (10,40 wt%) on the properties of polypropylene (PP) composites. The characteristics of the particulate fillers, such as mean particle size, particle size distribution, aspect ratio, shape, and degree of crystallinity were identified. In terms of mechanical properties, for all of the filled PP composites, Young's modulus increased, whereas tensile strength and strain at break decreased as the filler loading increased. However, 10 wt% of mica in a PP composite showed a tensile strength comparable with that of unfilled PP. Greater tensile strength of mica/PP composites compared to that of the other composites was observed because of lower percentages of voids and a higher aspect ratio of the filler. Mica/PP also exhibited a lower coefficient of thermal expansion (CTE) compared to that of the other composites. This difference was due to a lower degree of crystallinity of the filler and the CTE value of the mica filler. Scanning electron microscopy was used to examine the structure of fracture surfaces, and there was a gradual change in tensile fracture behavior from ductile to brittle as the filler loading increased. The nucleating ability of the fillers was studied with differential scanning calorimetry, and a drop in crystallinity of the composites was observed with the addition of mineral filler. Studies on the hybridization effect of different (silica and mica) filler ratios on the properties of PP hybrid composites showed that the addition of mica to silica-PP composites enhanced their tensile strength and modulus. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers [source] PVC nanocomposites,Nanoclay chemistry and performance,JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2008Daphne Benderly Nanoclay applications in poly(vinyl chloride) (PVC) have been limited, as the organic modifier of conventional nanoclays can promote PVC degradation. Novel nanoclays designed for enhanced PVC compatibility were compounded with PVC. Hectorite and bentonite clays were studied as nanoclay fillers. Two incorporation methods were evaluated to determine the effect on nanoclay dispersion and composite performance. A two-stage method, in which the nanoclay was predispersed in plasticizer, resulted in good nanoclay dispersion at both the micrometer and nanometer scales. The nanocomposites were characterized by using a wide range of analytical tools. They exhibited significantly improved heat stability, an increase of up to 200% in storage modulus, and a decrease of up to 77% in oxygen permeation, as compared to unfilled PVC. Bentonite nanoclays provided a greater increase in barrier and mechanical properties. No change was seen in the PVC glass transition temperature. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers [source] Polymer plasticization using supercritical carbon dioxide,JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2008Febe Kusmanto The plasticizing effect of supercritical CO2 (scCO2) during the extrusion of polymers was investigated. A modified extrusion system was used to demonstrate the viscosity-reducing effect of scCO2 together with a capability to produce foam-free extrudate with selected polymers, including poly(vinyl chloride). Samples of extrudate and materials prepared off-line by using a pressure vessel were characterized by thermal, mechanical, and X-ray techniques. After gas diffusion from the polymer, there was no long-term effect on polymer structure and properties. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Use of N -(N,-arylamino)maleimides to improve the thermal properties of poly(vinyl chloride) through chemical modification and graft copolymerizationJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2008Abir S. Abdel-Naby The reaction of poly(vinyl chloride) (PVC) with N -(N,-arylamino)maleimide derivatives was studied. The thermal stability of the modified polymer was improved markedly when compared with that of the unmodified polymer. The stability improvement was attributed to the replacement of the labile chlorine atoms by more stable organic groups. The modified polymer also showed a lower extent of discoloration when compared with that of unmodified PVC. In order to introduce a polymeric stabilizer into PVC, the dienophilic monomer was chemically grafted onto the polymeric chains. The mechanism of the chemical modification as well as that of the graft copolymerization are discussed. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Peroxide crosslinking of rigid poly(vinyl chloride)JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2008Anoma Gunewardena Peroxide crosslinking of unplasticized poly(vinyl chloride) with trimethylolpropane trimethacrylate was investigated. Formulations used in this work contained a nontoxic lead-free stabilizer and showed good color and heat stability. The samples were examined by differential scanning calorimetry, and their tensile properties were measured at room temperature and at 130°C. Gel content or tetrahydrofuran-insoluble material was measured as an indication of crosslinking. It was shown that premature crosslinking could be avoided during processing and that 190°C was the optimum processing temperature for maximum gel content. The residual unsaturation was monitored by using FTIR spectroscopy. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers [source] Nanoscopic characterization of a plastisol gelation and fusion process utilizing scanning electron microscopy and atomic force microscopyJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2008Jerome S. Jourdan Understanding the physical properties associated with the gelation and fusion of a PVC plastisol will help to improve process efficiency. Plastisol gelation and fusion were characterized by using both scanning electron microscopy (SEM) and atomic force microscopy (AFM) and were compared with the tensile properties developed at various temperatures. Both SEM and AFM showed good agreement during the early stages of gelation. However, AFM continued to show particle boundaries during the latter stages of gelation and fusion that provided a more nearly accurate comparison with the resulting tensile properties. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] The melting temperature (or not melting) of poly(vinyl chloride)JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2008James W. Summers The best answer to what is the melting temperature of PVC is its previous processing temperature. That temperature is where secondary crystallites, created by gelation, melt and allow the primary particle flow units to flow again independently. In the case of powder compounds being processed for the first time, the question of melting is less relevant. The PVC, out of the polymerizer, contains crystallites that are not completely meltable. The issue is how easily the grains of PVC disperse to primary particle flow units. This property depends on polymerization conditions and the type of processing equipment. The temperature achieved affects the amount of fusion (gelation). J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Studies on rheology and morphology of POE/PP thermoplastic elastomer dynamically crosslinked by peroxideJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2008Bo Yuan An ethylene-octene copolymer (POE)/polypropylene (PP) thermoplastic elastomer was prepared through dynamically crosslinking by 2,5-dimethyl-2,5-dilbuty (Peroxy) hexane (DHBP). The effects of DHBP concentration, POE/PP ratio, melt flow index (MFI) of PP, and mixer rotation on rheology and morphology of the thermoplastic elastomer were studied. The results showed that with increasing DHBP concentration or POE content, the size of crosslinked particles as well as the melt viscosity increased. Furthermore, agglomerates or a network structure formed as the size of crosslinked particles increased. The melt viscosity also increased as MFI of PP decreased, while the size of crosslinked particles decreased under the same condition. Research on the morphology of dynamically crosslinked POE/PP thermoplastic elastomer flowing through a capillary rheometer at different shear rates show that the reprocessing had little effect on the morphology of dynamically crosslinked elastomer. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Influence of third component on mechanical properties and thermal stability of polypropylene/(regenerated polyurethane) blendsJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2008Shu Ling Zhang The possibility of polypropylene (PP) modification by regenerated polyurethane (PU), obtained after partial thermochemical decomposition of waste PU, has been studied. The degradation product was a thermoplastic mixture, applicable for reuse without any purification and fractionation. It was proved that regenerated PU could be reused as an effective polymeric plasticizer for PP and that the addition of regenerated PU did not decrease the thermal stability of PP. In order to improve further the elongation at break of PP modified by regenerated PU, a third component was added to the PP/(regenerated PU) blend. The influence of the third component on the mechanical properties and thermal stability of the blends was evaluated by using a universal testing machine (UTM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The data showed that the elongations of PP/(regenerated PU) blends with styrene-ethylene-butylene-styrene polymer (SEBS) were obviously better than those of the PP/(regenerated PU) blend without the third component and with PP- g -MA or SEBS- g -MA (MA = maleic anhydride). In addition, the thermal stability of PP/(regenerated PU) blends with a third component was almost same as that of the PP/(regenerated PU) blend without a third component. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Reinforcement of rigid PVC/wood-flour composites with multi-walled carbon nanotubesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2008Omar Faruk Multi-walled carbon nanotubes (CNT) were compounded with PVC by a melt blending process based on fusion behaviors of PVC. The effects of CNT content on the flexural and tensile properies of the PVC/CNT composites were evaluated in order to optimize the CNT content. The optimized CNT-reinforced PVC was used as a matrix in the manufacture of wood-plastic composites. Flexural, electrical, and thermal properties of the PVC/wood-flour composites were evaluated as a function of matrix type (nonreinforced vs. CNT-reinforced). The experimental results indicated that rigid PVC/wood-flour composites with properties similar to those of solid wood can be made by using CNT-reinforced PVC as a matrix. The CNT-reinforced PVC did not influence the electrical and thermal conductivity of the PVC/wood-flour composites. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] Plate-out in PVC extrusion.JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2008Samples of extruder plate-out from industrial rigid PVC production lines were investigated by using a number of analytical techniques. The combined use of SEM-EDX (scanning electron microscopy , energy dispersive X-ray analysis), thermal analysis, FTIR (Fourier transform infrared spectrophotometry), and LIMA (laser-induced mass analysis) enabled most plate-out components to be identified and linked to likely formulation ingredients. The FTIR and thermal analyses were used to identify organic components. The FTIR analysis was also useful for identifying some inorganic compounds present in sufficient quantities, while EDX detected the elements present. The LIMA was the most sensitive technique, detecting trace quantities of both cations and anions. Calcium carbonate, titanium dioxide, and lead stabilizers were found in all die plate-out samples studied, together with small amounts of lubricants. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] | ||||||||||