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Rigid Poly (rigid + poly)
Selected AbstractsEffect 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] 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] 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] Wood/plastic composites co-extruded with multi-walled carbon nanotube-filled rigid poly(vinyl chloride) cap layerPOLYMER INTERNATIONAL, Issue 5 2010Shan Jin Abstract Wood/plastic composites (WPCs) can absorb moisture in a humid environment due to the hydrophilic nature of the wood in the composites, making products susceptible to microbial growth and loss of mechanical properties. Co-extruding a poly(vinyl chloride) (PVC)-rich cap layer on a WPC significantly reduces the moisture uptake rate, increases the flexural strength but, most importantly, decreases the flexural modulus compared to uncapped WPCs. A two-level factorial design was used to develop regression models evaluating the statistical effects of material compositions and a processing condition on the flexural properties of co-extruded rigid PVC/wood flour composites with the ultimate goal of producing co-extruded composites with better flexural properties than uncapped WPCs. Material composition variables included wood flour content in the core layer and carbon nanotube (CNT) content in the cap layer of the co-extruded composites, with the processing temperature profile for the core layer as the only processing condition variable. Fusion tests were carried out to understand the effects of the material compositions and processing condition on the flexural properties. Regression models indicated all main effects and two powerful interaction effects (processing temperature/wood flour content and wood flour content/CNT content interactions) as statistically significant. Factors leading to a fast fusion of the PVC/wood flour composites in the core layer, i.e. low wood flour content and high processing temperature, were effective material composition and processing condition parameters for improving the flexural properties of co-extruded composites. Reinforcing the cap layer with CNTs also produced a significant improvement in the flexural properties of the co-extruded composites, insensitive to the core layer composition and the processing temperature condition. Copyright © 2009 Society of Chemical Industry [source] | ||||||||||