Rheological and mechanical properties of poly(vinyl chloride)/chlorinated poly(vinyl chloride) miscible blends

The properties of poly(vinyl chlorlde)/ehlorinated poly(vinyl chloride) (61.6 percent C1) blends, prepared by melt and solution blending, were measured by various tests. Based on the chlorinated poly(vinyl chloride) (CPVC) composition, percent chlorine, and mole percent CC1₂ groups, these blends were expected to show intermediate properties between miscible and immiscible systems. Indicative of miscible behavior were the single glass transition temperatures over the entire composition range for both melt and solution blended mixtures. A single phase was also indicated by transmission electron microscopy. However, the yield stress showed a minimum value less than either of the pure components in the 50 to 75 percent CPVC range, which is characteristic of two-phased systems. Specific volume, glass transition temperature, and heat distortion temperature were linear with binary composition. The storage modulus showed a small maximum, suggesting a weak interaction between the two miscible polymers. Heats of melting for the residual PVC crystallinity were also less than expected from linear additivity. At 160°C and 210°C, the logarithm of the complex viscosity was essentially linear with volume fraction of CPVC, except for a very slight decrease in the 50 to 75 percent CPVC range, which may have been a result of lower crystallinity. At 140°C, the complex viscosity of the CPVC was less than that of PVC owing to the higher crystallinity of the latter. The viscosities were similar at 160°C, but at 210°C, where most of the crystallites had melted, the complex viscosity of the CPVC was higher because of its higher glass transition temperature.     

Free volume microprobe studies on poly(methyl methacrylate)/poly(vinyl chloride) and poly(vinyl chloride)/polystyrene blends

Blends of Poly(methyl methacrylate) (PMMA)/Poly(vinyl chloride) (PVC) and Poly(vinyl chloride) (PVC)/Polystyrene (PS) of different compositions were prepared by solution casting technique. The blends were characterized using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and Positron Lifetime Spectroscopy. DSC data were found to be inadequate to describe whether PMMA/PVC blends are miscible or not, possibly because of the small gap in their glass transition temperatures. On the other hand, PVC/PS blends were clearly found to be immiscible by DSC. FTIR results for PMMA/PVC indicate the possible interactions between the carbonyl group of PMMA and α‐hydrogen of PVC. Free volume data derived from Positron lifetime measurements showed that the PMMA/PVC blends to be miscible in low PVC concentration domain. For the first time, the authors have evaluated the hydrodynamic interaction parameter α, advocated by Wolf and Schnell, Polymer, 42, 8599 (2001), to take into account the friction between the component molecules using the free volume data. This parameter (α) has a high value (?57) at 10 wt% of PVC, which could be taken to read miscibility for PMMA/PVC blends to be high. In the case of PVC/PS blends, the positron results fully support the DSC data to conclude the blends to be immiscible throughout the range of concentration. As expected, the hydrodynamic interaction parameter α does not show any change throughout the concentration in PVC/PS blends, further supporting the idea that α is another suitable parameter in the miscibility study of polymer blends. POLYM. ENG. SCI., 46:1231–1241, 2006. © 2006 Society of Plastics Engineers     

Thermal stability of poly(vinyl chloride)/polyurethane blends

The thermal stability of poly(vinyl chloride) (PVC) and thermoplastic polyurethane (PU) blends has been studied in this work. It has been found that the PVC/PU blends possess lower thermal stability than unmodified PVC. No effect of the structure of polyurethanes or their content on the stability of PVC/PU system has been found.     

Miscibility,phase behavior,and mechanical properties of ternary blends of poly(vinyl chloride)/polystyrene/chlorinated polyethylene-graft-polystyrene

The effectiveness of chlorinated polyethylene-graft-polystyrene (CPE-g-PS) as a polymeric compatibilizer for immiscible poly(vinyl chloride)/polystyrene (PVC/PS) blends was investigated. The miscibility, phase behavior, and mechanical properties were studied using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), Izod impact tests, tensile tests, and scanning electron microscopy (SEM). DSC and DMA studies showed that PVC is immiscible with chlorinated polyethylene (CPE) in CPE-g-PS, whereas the PS homopolymer is miscible with PS in CPE-g-PS. The PVC/PS/CPE-g-PS ternary blends exhibit a three-phase structure: PVC phase, CPE phase, and PS phase that consisted of a PS homopolymer and PS in CPE-g-PS. The mechanical properties showed that CPE-g-PS interacts well with both PVC and PS and can be used as a polymeric compatibilizer for PVC/PS blends. CPE-g-PS can also be used as an impact modifier for both PVC and PS. SEM observations confirmed, after the addition of CPE-g-PS, improvement of the interfacial adhesion between the phases of the PVC/PS blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 995–1003, 1998     

PVC/G-POSS共混物的力学性能与热性能

考察了2,3-环氧丙氧乙基笼型倍半硅氧烷(G-POSS)对聚氯乙烯(PVC)共混物力学和热性能的影响。结果表明:加入G-POSS可缩短PVC的塑化时间;100 g PVC中G-POSS用量不超过7 g时共混物的拉伸强度得到提高;加入G-POSS可改善PVC的耐热性能,G-POSS用量为13 g时,共混物的维卡软化温度和初始分解温度分别提高12,27℃。     

Compatibilization of poly(vinyl chloride)/polystyrene blends with epoxidized styrene-butadiene-styrene block copolymers

The effectiveness of epoxidized styrene-butadiene-styrene (ESBS) block copolymer as a polymeric compatibilizer for the incompatible polystyrene/poly(vinyl chloride) (PS/PVC) blend was investigated. ESBS at two epoxidation levels (34 and 49 mol% oxirane units) was used and the study covered mainly compositions with up to 30 wt% PS content in the ternary blends. The results support the view that ESBS can serve as a compatibilizer at these levels of epoxidation and when added in amounts in excess of 5 wt%. Ternary blends may also have good elongation properties due to the thermoplastic elastomer character of ESBS.     

Miscibility in poly(vinyl chloride)/chlorinated poly(vinyl chloride) blends,and blends of different chlorinated poly(vinyl chlorides)

Blends of poly(vinyl chloride) with chlorinated poly(vinyl chloride) (PVC), and blends of different chlorinated poly(vinyl chlorides) (CPVC) provide an opportunity to examine systematically the effect that small changes in chemical structure have on polymer-polymer miscibility. Phase diagrams of PVC/CPVC blends have been determined for CPVC's containing 62 to 38 percent chlorine. The characteristics of binary blends of CPVC's of different chlorine contents have also been examined using differential calorimetry (DSC) and transmission electron microscopy. Their mutual solubility has been found to be very sensitive to their differences in mole percent CCl₂ groups and degree of chlorination. In metastable binary blends of CPVC's possessing single glass transition temperatures (T_g) the rate of phase separation, as followed by DSC, was found to be relatively slow at temperatures 45 to 65° above the T_g of the blend.     

Thermal and mechanical properties of poly(butylene terephthalate)/epoxy blends

In this study, melt blends of poly(butylene terephthalate) (PBT) with epoxy resin were characterized by dynamic mechanical analysis, differential scanning calorimetry, tensile testing, Fourier transform infrared spectroscopy, and wide‐angle X‐ray diffraction. The results indicate that the presence of epoxy resin influenced either the mechanical properties of the PBT/epoxy blends or the crystallization of PBT. The epoxy resin was completely miscible with the PBT matrix. This was beneficial to the improvement of the impact performance of the PBT/epoxy blends. The modification of the PBT/epoxy blends were achieved at epoxy resin contents from 1 to 7%. The maximum increase of the notched Izod impact strength (≈ 20%) of the PBT/epoxy blends was obtained at 1 wt % epoxy resin content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

顺酐化聚苯乙烯对PVC/SEBS共混物的增容作用

以顺酐化聚苯乙烯(PS-g-MAH)为增容剂,研究了苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)对聚氯乙烯(PVC)的共混增韧改性,讨论了该共混物在常温、低温下的力学性能及动态力学性能。结果表明,PS-g-MAH能明显改善SEBS与PVC的相容性,使PVC/SEBS共混物中分散相颗粒尺寸明显减小,分布更均匀,共混物的玻璃化转变温度内移,常温和低温下缺口冲击强度增大。当PVC/PS-g-MAH/SEBS(质量比)为75/6/25时,共混物的常温缺口冲击强度为50.6 kJ/m2,低温(-20℃)缺口冲击强度为29.8 kJ/m2。     

Dynamic mechanical properties of poly(vinyl chloride) and polyurethane carboxylate blends

The miscibility of thermoplastic polyurethane elastomers (TPUs) with poly(vinyl chloride) (PVC) was studied. PVC blends with TPUs, prepared from 4,4-diphenylmethane diisocyanate as diisocyanate, hydroxy-terminated poly(butylene adipate) (PBA) as the soft segment, and dimethylolpropionic acid as the chain extender carrying a latent anionic site for neutralization by triethylamine, showed a single glass transition temperature (T_g), irrespective of neutralization of latent anionic sites of TPU. But in neutralized TPU/PVC blends, limited intimate segmental mixing was perceived from the mechanical properties observed. When hydroxy-terminated poly(propylene glycol) was used as the soft segment instead of hydroxy-terminated PBA, PVC/TPU blends showed two separate T_g's of PVC and TPU, irrespective of neutralization. © 1994 John Wiley & Sons, Inc.     

Thermal analysis of irradiated poly(vinyl chloride)

The thermal decomposition and resultant disposal of waste poly(vinyl chloride) (PVC) is facilitated by preliminary exposure to ionizing radiation, such as energetic electrons, in an oxygen atmosphere. The results of isothermal and temperature-programmed thermogravimetry, differential thermal analysis, and effluent gas analysis in nitrogen and in oxygen indicate that the major effect of irradiation is to render PVC increasingly susceptible to oxidation. The presence of oxygen during heating enhances the decomposition. Crystalline order in PVC is destroyed by irradiation.     

Thermal degradation of poly(vinyl chloride) blends

Poly(vinyl chloride) was mixed with various poly(methacrylate)s and polycarbonates by combined precipitation from common solutions. The thermal stability of the samples was measured at 180°C under nitrogen, the HCl evolved was detected by conductometry. UV-Vis-spectra of degraded samples were measured to investigate the influence of the poly(methacrylate)s on the lengths of polyenes formed during the degradation of poly(vinyl chloride). The experiments show that the nature of the ester group is the dominating factor for the thermal stability of poly(vinyl chloride) in these blends. Poly(n-butylmethacrylate) exhibits the best stabilization for poly(vinyl chloride) in this series. Polycarbonates with a higher glass transition temperature than the temperature of degradation destabilize poly(vinyl chloride). Stabilization experiments with dibutyltin-bis(isooctylthioglycolate) show a costabilizing effect of the poly(methacrylate)s and polycarbonates.     

Thermal and dynamic mechanical behavior of poly(vinyl chloride)/wood flour composites

Thermal and dynamic mechanical behaviors of wood plastic composites made of poly vinyl chloride (PVC) and surface treated, untreated wood flour were characterized by using differential scanning calorimetry and dynamic mechanical analysis. Glass transition temperature (T_g) of PVC was slightly increased by the addition of wood flour and by wood flour surface treatments. Heat capacity differences (ΔC_p) of composites before and after glass transition were markedly reduced. PVC/wood composites exhibited smaller tan δ peaks than PVC alone, suggesting that less energy was dissipated for coordinated movements and disentanglements of PVC polymer chains in the composites. The rubbery plateaus of storage modulus (E′) curves almost disappeared for PVC/wood composites in contrast to a well defined plateau range for pure PVC. It is proposed that wood flour particles act as “physical crosslinking points” or “pinning centers” inside the PVC matrix, resulting in the absence of the rubbery plateau and high E′ above T_g. The mobility of PVC chain segments were further retarded by the presence of surface modified wood flour. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Behavior of flexible poly(vinyl chloride)/poly(hydroxybutyrate valerate) blends

Blends of flexible poly(vinyl chloride) (PVC) and a poly(hydroxybutyrate valerate) (PHBV) copolymer were prepared and characterized with different techniques. The tensile strength of PVC did not show a marked reduction at PHBV concentrations up to 50 phr, despite a lack of miscibility between the two polymers. The crystallization of the PHBV copolymer was markedly hindered by the presence of PVC, as calorimetric results revealed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Thermal degradation of ternary blends of poly(ε‐caprolactone)/poly(vinyl acetate)/poly(vinyl chloride)

The thermal degradation of ternary blends of poly(ε‐caprolactone) (PCL), poly(vinyl acetate) (PVAC), and poly(vinyl chloride) (PVC) was studied using a thermogravimetry analyzer under dynamic heating in flowing nitrogen atmosphere. PCL degraded in a single stage, whereas the PVAC and PVC degraded in two stages during which acid is released in the first stage followed by backbone breakage in the second stage. The addition of PVC to either PCL or PVAC affected the thermal stability of the blend, whereas the addition of PVAC to PCL did not alter the thermal stability of the blend. In ternary blends, the addition of PVC affected the degradation of PVAC but did not influence the degradation of PCL in the range investigated. The increased addition of PCL to the binary blends of PVC/PVAC decreased the extent of thermal instability of PVAC because of the addition of PVC. The addition of even 10% PVAC to the PCL/PVC blend removed the thermal instability of PCL resulting from the addition of PVC and can be attributed to the ease of chlorine or hydrogen chloride capture of PVAC over PCL. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1378–1383, 2004     

The effect of layered double hydroxides dispersion on thermal and mechanical properties of poly(vinyl chloride)/poly(methyl methacrylate) blends

Poly(vinyl chloride) (PVC)/layered double hydroxide (LDH) composites and PVC/poly(methyl methacrylate) (PMMA)/LDH composites were prepared via solution intercalation into PVC using both unmodified and organo‐modified LDHs and variable‐molecular‐weight PMMA as additional components. The LDH dispersion was investigated using X‐ray diffraction analysis and electron microscopy in scanning and transmission modes. Spotlight fourier transform infrared (FTIR) chemical imaging analysis was also used to obtain a deeper insight into the dispersion of polymer phases and LDH segregation. Thermal properties were determined using thermogravimetric analysis and differential scanning calorimetry; moreover, a preliminary investigation of mechanical properties in tensile mode and evaluation of the Vicat softening temperature were carried out. The morphological analysis of PVC/LDH and PVC/PMMA/LDH composites evidenced in both cases the presence of disordered micro‐aggregates with loss of the LDH crystallographic symmetry depending on the amount and molecular weight of PMMA. In particular, in the case of PVC/PMMA/LDH composites, the FTIR imaging analysis showed that PMMA mostly segregated in the LDH phase. However, even if the degree of LDH dispersion was not elevated (micro‐aggregates with disordered structures and size ranging from 0.5 up to 11 µm were evidenced), thermal stability and mechanical properties of the composites were improved with a synergic effect of PMMA and LDH. © 2013 Society of Chemical Industry     

Morphology and mechanical properties of poly(propylene)/polystyrene blends compatibilized with polystyrene-block-poly(ethylene-co-propylene)

Compatibilizing effects of diblock copolymer polystyrene-block-poly(ethylene-co-propylene) (SEP) on the morphology and mechanical properties of immiscible blends of poly(propylene) (PP) and polystyrene (PS) were investigated. Notched impact strength, yield stress, elongation at yield and Young's modulus were determined as a function of different weight ratios of PP and PS and different amounts of added SEP as well. Scanning electron microscopy revealed a two-phase morphology of PP/PS blends, which exhibit poor mechanical properties. Even 2,5 wt.-% of SEP added to PP/PS blends can improve the notched impact strength and elongation at yield compared to non-compatibilized PP/PS blends. 10 wt.-% of SEP compatibilizer converted the brittle PP/PS blend to quite impactresistant polymeric material. Mechanical properties were improved because of the morphological changes and increased interfacial adhesion as a result of SEP localization between PP and PS phases. An analysis of yield stress data in terms of theoretical models showed that yield stress values of binary PP/PS blends can be predicted with Nielsen's model.     

Crystallization behavior and mechanical properties of poly(ethylene oxide)/poly(L‐lactide)/poly(vinyl acetate) blends

Poly(vinyl acetate) (PVAc) was added to the crystalline blends of poly(ethylene oxide) (PEO) and poly(L ‐lactide) (PLLA) (40/60) of higher molecular weights, whereas diblock and triblock poly(ethylene glycol)–poly(L ‐lactide) copolymers were added to the same blend of moderate molecular weights. The crystallization rate of PLLA of the blend containing PVAc was reduced, as evidenced by X‐ray diffraction measurement. A ringed spherulite morphology of PLLA was observed in the PEO/PLLA/PVAc blend, attributed to the presence of twisted lamellae, and the morphology was affected by the amount of PVAc. A steady increase in the elongation at break in the solution blend with an increase in the PVAc content was observed. The melting behavior of PLLA and PEO in the PEO/PLLA/block copolymer blends was not greatly affected by the block copolymer, and the average size of the dispersed PEO domain was not significantly changed by the block copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3618–3626, 2001