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PVC/PMMA Blends (pvc + blend)
Selected AbstractsCrystallization of Poly(, -caprolactone)/Poly(vinyl chloride) Miscible Blends Under Strain: The Role of Molecular WeightMACROMOLECULAR RAPID COMMUNICATIONS, Issue 18 2006Yubao Zhang Abstract Summary: The effect of poly(, -caprolactone) (PCL) molecular weight on the orientation of crystalline PCL in miscible poly(, -caprolactone)/poly(vinyl chloride) (PCL/PVC) blends, melt crystallized under strain, has been studied by a combination of wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS) studies. An unusual crystal orientation with the b-axis parallel to the stretching direction was observed in miscible PCL/PVC blends with PCL of high molecular weight (>21,000). SAXS showed the presence of nanosize confined PCL in the PCL/PVC blends, which could be preserved at temperatures higher than the Tm of PCL but lower than the Tg of PVC. A mechanism based on the confinement of PCL crystal growth was proposed, which can explain the formation of b-axis orientation in PCL/PVC blends crystallized under strain. SAXS pattern of stretched PCL/PVC blend after annealing at 90,°C for 5 min. [source] Compatibilization of poly(vinyl chloride) with polyamide and with polyolefin by using poly(lauryllactam- random -caprolactam- block -caprolactone)JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2005In Kim The compatibilization of various poly(vinyl chloride) (PVC) blends was investigated. The blend systems were PVC-polyamide 12 (PA12), PVC-polypropylene (PP), and PVC-ethylene-propylene-diene rubber (EPDM) with a new compatibilizing agent, random-block terpolymer poly(,-lauryllactam- random -,-caprolactam- block -,-caprolactone) or systems containing these copolymers. The results were compared to those obtained in previous studies using poly(,-lauryllactam- block -,-caprolactone) copolymer. The new block copolymer was specially synthesized by reactive extrusion. Observation by scanning electron microscopy (SEM) revealed that compatibilized blends had a finer morphology than the noncompatibilized blends. Addition of 10 weight percent (wt%) of block copolymer proved to be sufficient to give a significant improvement of the mechanical properties of the immiscible PVC blends at room temperature and at high temperatures that were above the glass transition temperature of PVC. For polyolefins, a three-component compatibilizing system including maleated polypropylene, polyamide 12, and block copolymer was used. It was found that poly(,-lauryllactam- random -,-caprolactam- block -,-caprolactone) was the more efficient compatibilizing agent for the modification of PVC-polyamide 12, PVC-polypropylene, and PVC-ethylene-propylene-diene rubber blends. J. VINYL. ADDIT. TECHNOL., 11:95,110, 2005. © 2005 Society of Plastics Engineers [source] Effect of electron-beam irradiation on poly(vinyl chloride)/epoxidized natural rubber blend: dynamic mechanical analysisPOLYMER INTERNATIONAL, Issue 5 2001Chantara Thevy Ratnam Abstract The irradiation-induced crosslinking in 50/50 poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blend was investigated by means of dynamic mechanical analysis. The influence of trimethylolpropane triacrylate on the irradiation-induced crosslinking of PVC/ENR blends was also studied. The enhancement in storage modulus and Tg with irradiation dose indicated the formation of irradiation-induced crosslinks. This is further supported by the decrease in tan ,max and loss modulus peak. The compatibility of the blend was found to be improved upon irradiation. The Fox model was used to provide a further insight into the irradiation-induced compatibility in the blend. Scanning electron microscopy studies on the cryofracture surface morphology of the blends as well as the homopolymer have been undertaken in order to gain more evidence on the irradiation-induced crosslinking. © 2001 Society of Chemical Industry [source] Investigation of the phase morphology of dynamically vulcanized PVC/NBR blends using atomic force microscopyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010S. M. Gheno Abstract Dynamic vulcanization is a mixing process employed in the melt state of elastomers with thermoplastics. This process may result in the formation of thermoplastic vulcanized (TPV) materials with improved properties such as mechanical strength, Young's modulus, hardness, and abrasion fatigue. In this study, a vulcanized thermoplastic was obtained by the dynamic vulcanization of poly(vinyl chloride)/acrylonitrile butadiene rubber (PVC/NBR) blends using a curative system based on sulfur (S)/tetramethylthiuram disulfide (TMTD) and mercaptobenzothiazyl disulfide (MBTS). The formation of crosslinks was characterized by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The mechanical properties were analyzed by tensile tests and the phase morphology was investigated using atomic force microscopy (AFM) operating in the tapping mode-AFM. The phase images of the dynamically vulcanized blends showed an elongated morphology, which can be associated to the formation of crosslinks that give the material its excellent mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] PVC modification through polymerization of a monomer absorbed in porous suspension-type PVC particlesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2004M. Narkis In-situ polymerization is the polymerization of one monomer in the presence of another polymer. It can be performed by sequential emulsion polymerization, or by reactions in the melt, in the solid phase, or in solution. The current report describes two methods to obtain poly(vinyl chloride) (PVC) modification through polymerization of a monomer absorbed in commercial porous suspension-type PVC particles. The generated modified PVC products differ significantly in their structure and properties. The first approach includes absorption of a monomer/peroxide solution within porous suspension-type PVC particles, followed by polymerization/crosslinking in the solid state at 80°C in an aqueous stabilizer-free dispersion. The monomer/crosslinker pairs selected are styrene/DVB (divinyl benzene), methylmethacrylate/EGDMA (ethylene glycol dimethacrylate), butyl acrylate/EGDMA, and ethylhexyl acrylate/EGDMA. The influence of composition and nature of the polymerizing/crosslinking constituents on the modified PVC particle structure was studied by microscopy methods, porosity measurements, and dynamic mechanical behavior (DMTA). The level of molecular grafting between PVC and the modifying polymer was determined by solvent extraction experiments. This work shows that the different monomers used represent distinct courses of monomer transport through the PVC particles. The characteristics of the modified PVC particle indicate that the polymerization/crosslinking process occurs in both the PVC bulk, i.e., within the walls constituting a particle, and in the PVC pores. No indication of chemical intermolecular interaction within the modified PVC particles was found. In the second approach, a solution of monomer, initiator, and a crosslinking agent is absorbed in commercial suspension-type porous PVC particles, thus forming a dry blend. This dry blend is subsequently reactively polymerized in a twin-screw extruder at an elevated temperature, 180°C, in the molten state. The properties of the reactively extruded PVC/PMMA blends are compared with those of physical blends at similar compositions. Owing to the high polymerization temperature, short-chain polymers are formed in the reactive polymerization process. Reactively extruded PVC/PMMA blends are transparent, form single-phase morphology, have a single Tg, and show mechanical properties comparable with those of the neat PVC. The resulting reactively extruded PVC/PMMA blends have high compatibility. J. Vinyl Addit. Technol. 10:109,120, 2004. © 2004 Society of Plastics Engineers. [source] Structure of reactively extruded rigid PVC/PMMA blendsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2005Y. Haba Abstract A novel route for producing polymer blends by reactive extrusion is described, starting from poly (vinyl chloride)/methyl methacrylate (PVC/MMA) dry blend and successive polymerization of MMA in an extruder. Small angle X-ray scattering (SAXS) measurements were applied to study the monomer's mode of penetration into the PVC particles and to characterize the supermolecular structure of the reactive poly(vinyl chloride)/poly(methyl methacrylate) (PVC/PMMA) blends obtained, as compared to the corresponding physical blends of similar composition. These measurements indicate that the monomer molecules can easily penetrate into the PVC sub-primary particles, separating the PVC chains. Moreover, the increased mobility of the PVC chains enables formation of an ordered lamellar structure, with an average d -spacing of 4.1,nm. The same characteristic lamellar structure is further detected upon compression molding or extrusion of PVC and PVC/PMMA blends. In this case the mobility of the PVC chains is enabled through thermal energy. Dynamic mechanical thermal analysis (DMTA) and SAXS measurements of reactive and physical PVC/PMMA blends indicate that miscibility occurs between the PVC and PMMA chains. The studied reactive PVC/PMMA blends are found to be miscible, while the physical PVC/PMMA blends are only partially miscible. It can be suggested that the miscible PMMA chains weaken dipole,dipole interactions between the PVC chains, leading to high mobility and resulting in an increased PVC crystallinity degree and decreased PVC glass transition temperature (Tg). These phenomena are shown in the physical PVC/PMMA blends and further emphasized in the reactive PVC/PMMA blends. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||