			Home About us Contact

Reactive Compatibilization (reactive + compatibilization)

Distribution by Scientific Domains

Polymers and Materials Science	100%

Selected Abstracts

Reactive compatibilization of biodegradable poly(lactic acid)/poly(,-caprolactone) blends with reactive processing agents

POLYMER ENGINEERING & SCIENCE, Issue 7 2008
Masaki Harada
Poly(lactic acid) (PLA) blended with poly(,-caprolactone) (PCL) was prepared with various reactive processing agents. Four isocyanates-lysine triisocyanate (LTI); lysine diisocyanate (LDI); 1,3,5-tris(6-isocyanatohexyl)-1,3,5-triazinane-2,4,6-trione (Duranate TPA-100); 1,3,5-tris(6-isocyanatohexyl)biuret (Duranate 24A-100)-and an industrial epoxide-trimethylolpropane triglycidyl ether (Epiclon 725)-were used as reactive processing agents. PLA/PCL blended in the presence of LTI had the highest torque in a mixer test. The test specimens were prepared by injection molding. The mechanical properties, thermal properties, molecular weight, melt viscosity, phase behavior, and morphology were investigated using tensile strength, impact strength, differential scanning calorimetry, melt mass-flow rate measurements, capillary rheometery, gel permeation chromatography, laser scanning confocal microscopy (LSCM), and visco-elasticity atomic force microscopy (VE-AFM). The impact strength increased considerably at 20 wt% PCL. The nominal tensile strain of PLA/PCL blended with LTI increased by 270%. The MFR values of PLA/PCL blends decreased with increasing LTI. Similar results were observed for shear viscosity. LSCM measurements showed that the diameters of PCL were dispersed about 0.4 ,m in the presence of LTI. VE-AFM showed that spherical particles with diameters of 50 nm were PCL-rich domain. These results indicate that isocyanate groups of LTI react with both terminal hydroxyl or carboxyl groups of polymers, and the compatibility of PLA/PCL blends improves with LTI by reactive processing. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source]

Reactive blending of poly (dimethylsiloxane) with nylon 6 and poly (styrene):Effect of reactivity on morphology

POLYMER ENGINEERING & SCIENCE, Issue 4 2001
M. Mari
Reactive compatibilization was used to control and stabilize 20,30wt% poly(dimethylsioxane) (PDMS) dispersions in nylon 6 (PA) and poly(styrene) (PS), respectively. The effect of the type of reation (amine (NH2)/anhydride (An), NH2/ epoxy(E) and carboxylic acid (COOH)/E) on the morphology was studied with electron microscopy. PS and PDMS have mutual solvents thus it was possible to use gel permeation chromatography (GPC) to determine the concentration of block copolymer in PS/PDMS blends. Reactive blending of PA6 with difunctional PDMS-(AN)2 did not decrease the PDMS particle size compared to the non-reactive blend (,10,m). Particle size decreaeased significantly to about 0.5 ,m when PA6 was blended with a PDMS containing about 4 random An groups along the chain. For the PS/PDMS blends, GPC revealed that the NH2/An reaction formed about 3% block copolymer and produced stable PDMS particles , 0.4 ,m. No reaction was detected for the PS-NH2/PDMS-E blend and the morphology was coarse and unstable. Also, PS-NH2/PDMS-An reactivity was lower compared to other systems such as PS/ poly (isoprene) and PS/poly(methaacrylte) using the same reaction. This was attributed to the relatively thinner PS/PDMS interface dueto the high PS/PDMs immiscibility. [source]

Reactive compatibilization of nylon copolymer/EPDM blends: experimental aspects and their comparison with theory

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2008
Cibi Komalan
Abstract In situ reactive compatibilization was first time applied to a low melting nylon (nylon 6 and 66 copolymer) and EPDM blend system. The effects of in situ compatibilization and concentration of compatibilizer on the morphology and mechanical properties of nylon/EPDM blends have been investigated. The influence of EPM-g-MA on the phase morphology was examined by the scanning electron microscopy (SEM) after preferential extraction of the minor phase. The SEM micrographs were quantitatively analyzed for domain size measurements. The compatibilizer concentrations used were 0, 1, 2.5, 5, and 10,wt%. The graft copolymer (nylon-g-EPM) formed at the interface showed relatively high emulsifying activity. A maximum phase size reduction was observed when 2.5,wt% of compatibilizer was added to the blend system. This was followed by a leveling-off at higher loadings indicating interfacial saturation. The conformation of the compatibilizer at the interface was deduced based on the area occupied by the compatibilizer at the blend interface. The experimental compatibilization results were compared with theoretical predictions of Noolandi and Hong. It was concluded that the molecular state of compatibilizer at interface changes with concentration. The in situ compatibilized blends showed considerable improvement in mechanical properties. Measurement of tensile properties shows increased elongation as well as enhanced modulus and strength up on compatibilization. At higher concentrations of compatibilizer, a leveling-off of the tensile properties was observed. A good correlation has been observed between the mechanical properties and morphological parameters. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Morphology and thermal properties of a PC/PE blend with reactive compatibilization

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2007
Bo Yin
Abstract Reactive compatibilization of immiscible polymers is becoming increasingly important and hence a representative study of a polycarbonate/high density polyethylene (PC/HDPE) system is the focus of this paper. A grafted copolymer PC- graft -ethylene- co -acrylic acid (PC- graft -EAA) was generated as a compatibilizer in situ during processing operation by ester and acid reaction between PC and ethylene-acrylic acid (EAA) in the presence of the catalyst dibutyl tin oxide (DBTO). As the polyethylene (PE) matrix does not play any part during the synthesis of the copolymer and since PC and EAA are also immiscible, to simplify the system, the influence of this copolymer formation at the interface between PC and EAA on rheological properties, phase morphology, and crystallization behavior for EAA/PC binary blends was first studied. The equilibrium torque increased with the DBTO content increasing in EAA/PC blends on Haake torque rheometer, indicating the in situ formation of the graft copolymer. Scanning electron microscopy (SEM) studies of cryogenically fractured surfaces showed a significant change at the distribution and dispersion of the dispersed phase in the presence of DBTO, compared with the EAA/PC blend without the catalyst. Differential scanning calorimetry (DSC) studies suggested that the heat of fusion of the EAA phase in PC/EAA blends with or without DBTO reduced with the formation of the copolymer compared with pure EAA. Then morphological studies and crystallization behavior of the uncompatibilized and compatibilized blends of PC/PE were studied as functions of EAA phase concentration and DBTO content. Morphological observations in PC/PE blends also revealed that on increasing the EAA content or adding the catalyst DBTO, the number of microvoids was reduced and the interface was intensive as compared to the uncompatibilized PC/PE blends. Crystallization studies indicated that PE crystallized at its bulk crystallization temperature. The degree of crystallinity of PE phase in PC/PE/EAA blends was also reduced with the addition of EAA and DBTO compared to the uncompatibilized blends of PC/PE, indicating the decrease in the degree of crystallinity was more in the presence of PC- graft -EAA. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Reactivity of common functional groups with urethanes: Models for reactive compatibilization of thermoplastic polyurethane blends

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2002
Qi-Wei Lu
Abstract Two model urethane compounds, dibutyl 4,4,-methylenebis(phenyl carbamate) (BMB) and dioctyl 4,4,-methylenebis(phenyl carbamate) (OMO) were prepared by capping 4,4,-methylenebis(phenyl isocyanate) with n -butanol and n -octanol, respectively. The reactions of the two model urethane compounds with several small monofunctional compounds as well as two model poly(ethylene glycols) were carried out with neat mixtures at elevated temperatures. The ranking of reactivity of the functional groups with the urethanes was determined as follows,primary amine > secondary amine , hydroxyl , acid , anhydride , epoxide. Nuclear magnetic resonance spectroscopy (NMR) was used for the quantitative analysis. Fourier transform infrared spectroscopy was used to complement the NMR analysis. Conversions of carbamate in each reaction were monitored over time at constant temperature (200 °C). The reactions between OMO and primary amine were conducted at 170, 180, 190, and 200 °C and best described with a second-order bimolecular reaction model. The rate constant was estimated to be 1.8 × 10,3 L · mol,1 · s,1 and activation energy 115 kJ · mol,1. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2310,2328, 2002 [source]

Injection moldability and properties of compatibilized PA6/LDPE blends

POLYMER ENGINEERING & SCIENCE, Issue 9 2004
L. Canfora
An ethylene-acrylic acid copolymer (EAA), either alone or combined with a low molar mass bis-oxazoline compound (PBO), has been used as a compatibilization promoter for blends of polyamide-6 (PA6) with low-density polyethylene (LDPE). The effect of compatibilization on blend processability in injection molding operations and on the properties of the molded specimens has been studied. In the absence of compatibilization, the injection molded articles were shown to have low-quality surface appearance and poor mechanical properties. Both these characteristics were appreciably improved as a result of reactive compatibilization of the blends with EAA and, even more, with the EAA-PBO couple. In fact, the finished articles prepared by injection molding of the quaternary blends were shown to possess good surface appearance, fine and stable morphology and satisfactory mechanical properties. The results confirm the conclusion of a previous study, i.e., that the PBO fourth component may promote the in situ formation of PA6- g -EAA copolymers, by reaction with both the functional groups of PA6 and the carboxyl groups of EAA. Polym. Eng. Sci. 44:1732,1737, 2004. © 2004 Society of Plastics Engineers. [source]

Blends of nylon/acrylonitrile butadiene rubber: Effects of blend ratio, dynamic vulcanization and reactive compatibilization on rheology and extrudate morphology

POLYMER ENGINEERING & SCIENCE, Issue 9 2003
C. Radhesh Kumar
The melt flow behavior of thermoplastic elastomers from nylon and nitrile rubber (NBR) was studied as a function of blend ratio, dynamic crosslinking, compatibilization and temperature. The morphology of the extrudates, i.e., the size, shape and distribution of the domains, was analyzed. Uncompatibilized and compatibilized blends showed pseudoplastic behavior. The viscosity of the blends showed positive deviation from a linear rule of mixtures. Compatibilization using chlorinated polyethylene (CPE) increased the melt viscosity of the blends. The addition of the compatibilizer decreased the domain size of the dispersed phase, followed by an increase after a critical concentration of the compatibilizer, where the interface was saturated. The influence of dynamic vulcanization on the rheological behavior was also studied. The extrudate morphology depended on blend ratio, compatibilization and shear rate. [source]