Comparison of the toughening mechanisms of poly(vinyl chloride)/chlorinated polyethylene and poly(vinyl chloride)/acrylonitrile–butadiene–styrene copolymer blends

In this study, the influence of chlorinated polyethylene (CPE) and acrylonitrile–butadiene–styrene copolymer (ABS) on the mechanical properties of poly(vinyl chloride) (PVC)/CPE and PVC/ABS hybrids were examined. The experimental results show that the toughness of the hybrids could be modified greatly by the introduction of CPE or ABS. The microstructure and impact surfaces of the blends were investigated by scanning electron microscopy and transmission electron microscopy. ABS dispersed in the form of particles or agglomerates in the PVC matrix, and CPE tended to disperse as a net structure. In the tensile test, ABS initiated crazes as stress concentrators to toughen the PVC matrix, whereas CPE, with the PVC matrix together, caused a yield deformation by shear stress to form a shear band. The formation of crazes and shear bands benefited the toughening of PVC, but to the different extent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 916–924, 2003     

Investigation of the thermal,mechanical and morphological properties of poly(vinyl chloride)/polyhedral oligomeric silsesquioxane nanocomposites

Research into organic–inorganic nanocomposites has recently become popular, particularly the development of new polymer nanocomposites. Compared to pristine polymers or conventional composites, these nanocomposites exhibit improved properties. The storage modulus of a poly(vinyl chloride) (PVC)/polyhedral oligomeric silsesquioxane (POSS) nanocomposite slightly decreased with POSS content, but had a higher modulus from 50 to 100 °C. Some of the material appeared to be aggregated with 1 wt% POSS in the polymeric matrix. Conversely, with a POSS content of 5 wt%, a better dispersion of the nanoparticles was observed. The presence of POSS in the plasticised PVC compound had little influence on the final properties of the nanocomposites, showing weaker interactions between the POSS and the plasticised PVC compound. Copyright © 2010 Society of Chemical Industry     

Processability,rheology, and thermal,mechanical, and morphological properties of postconsumer poly(vinyl chloride) bottles and cables

The processability, rheology, and thermal, mechanical, and morphological properties of three different commercial poly(vinyl chloride) (PVC) compounds blended with postconsumer PVC bottles and PVC cables were examined with respect to the recycled PVC content. The addition of PVC bottle recyclates [recycled bottles (RBs)] into virgin PVC bottle (VB) and virgin PVC pipe (VP) compounds caused a progressive reduction in the average torque. No thermal degradation or color change in the RB‐blended PVC compounds used was detected through carbonyl and polyene indices from IR analysis. The rheological properties for VP compounds were more sensitive to RB addition than those of VB compounds. The extrudate swell ratio did not change with the RB content. The decomposition temperature for the VB and VP compounds increased at 60–80% RB, whereas the glass‐transition temperature was unaffected by the RB loading. The 20 and 80 wt % RB loadings were recommended for the VB and VP compounds, respectively, for the optimum impact strength, the blends showing ductile fracture with a continuous phase. At the optimum impact and tensile properties, introducing RB recyclates into the VB compounds gave better results than the VP compounds. The hardness and density of the VB and VP compounds did not change with the RB content. The RB property change was comparatively faster than that of recycled PVC pipes. Adding the PVC cable recyclate [recycled cable (RC)] to virgin PVC cable (VC) had no obvious effect on the torque value of the RC/VC blends. The decomposition temperatures of the RC/VC blends stabilized at 20–60% RC and tended to decrease at 80% RC. The ultimate tensile stress was improved by the addition of the RC compounds, whereas the hardness and density of the VC compounds were unaffected by the RC content. It was concluded that the optimum concentrations of PVC recyclates to be added to virgin PVC compounds were different from one property to another and also depended on the type of virgin PVC grade used. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2738–2748, 2003     

The influence of poly(vinyl alcohol) suspending agents on suspension poly(vinyl chloride) morphology

The requirements for PVC suspension resin have changed considerably in the last few years, so much so that few companies have products on their ranges that are more than 4 or 5 years old. The suspending agent has a crucial influence on the morphology of the resin, so the changes in resin characteristics have largely been achieved by changes in the suspending agent systems. After a brief review of the mechanism of PVC suspension polymerisation, the properties of polymers made using PVOH suspending agents are related to changes in the latter. The effect of variations in PVAc degree of hydrolysis and viscosity are related to changes in surface tension. Methods of achieving higher porosity by using low hydrolysis co-suspending agents are described. It is shown that higher bulk densities can be achieved by delayed addition of the PVOH. Levels of conjugated unsaturation and copolymer distributions are also shown to have important influences.     

Hydrothermic aging of plasticized poly(vinyl chloride): Its effect on the dielectric,thermal, and mechanical properties

Accelerated hydrolytic aging (according to the NFT 5166 method) was performed on samples of poly(vinyl chloride) (PVC) plasticized with dioctylphthalate (DOP) and dinonyladipate (DNA) at different concentration ratios. The aging test consisted of immersing the samples in boiling water at 100°C. The samples were removed from water regularly, that is, every 2 h, for mechanical, thermal, and dielectric characterizations. Thermograms of PVC plasticized with DOP revealed no migration of the plasticizer independent of the concentration used. Moreover, the thermal stability of the samples was not affected by the hydrothermal aging. However, for PVC samples plasticized with DNA, a small amount of the plasticizer migrated from the polymer matrix with a considerable effect on the thermal stability. In fact, the data indicated a decrease in the decomposition temperature from 275 to 225°C, particularly for samples containing 50% (w/w) DNA immersed up to 10 h. The mechanical results showed that for a plasticizer content greater than 30% (w/w), the strain at break obtained for samples plasticized with DNA was lower than that for samples plasticized with DOP because the DNA molecules were more likely to be removed by water on account of their polarity and dimension. Finally, the dielectric measurements showed that the permittivity of all the PVC samples plasticized with DOP and immersed in boiling water was higher than that of the virgin samples. On the contrary, the permittivity of the aged unplasticized PVC was less than that of the nonimmersed samples. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3447–3457, 2003     

Flame‐retardant properties of magnesium hydroxystannate and strontium hydroxystannate coated calcium carbonate on soft poly(vinyl chloride)

The flame‐retardant and smoke‐suppressant properties of soft poly(vinyl chloride) (PVC) treated with zinc hydroxystannate (ZHS), calcium carbonate (CaCO₃), magnesium hydroxystannate [MgSn(OH)₆], strontium hydroxystannate [SrSn(OH)₆], ZHS–MgSn(OH)₆, ZHS–SrSn(OH)₆, MgSn(OH)₆‐coated CaCO₃, SrSn(OH)₆‐coated CaCO₃, ZHS–MgSn(OH)₆‐coated CaCO₃, and ZHS–SrSn(OH)₆‐coated CaCO₃ were studied with the limited oxygen index, char yield, and smoke density rating methods; the mechanical properties were also studied. The results showed that, with the equivalent addition of the corresponding hydroxystannate, the soft PVC treated with hydroxystannate‐coated CaCO₃ had a higher limited oxygen index than the corresponding hydroxystannate, and the soft PVC treated with the agents containing magnesium had a higher limited oxygen index than the soft PVC treated with the agents containing strontium, except for ZHS–MgSn(OH)₆‐coated CaCO₃. The improvement in the char formation of the hydroxystannate‐coated CaCO₃ was better than that of the corresponding hydroxystannate in most cases, and the aforementioned agents reduced the smoke density rating, decreased the tensile strength, and increased the elongation and impact strength basically. Thermal analysis showed that the additives promoted the evolution of hydrogen chloride, early crosslinking, and rapid charring through the strong catalyzing effect of Lewis acids. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Studies on mechanical and rheological properties of poly(vinyl chloride) modified with elastomers and rigid organic particles

Chlorinated polypropylene (CPP) as rigid organic particles and chlorinated polyethylene (CPE) as elastomer were used to modify the properties of poly(vinyl chloride) (PVC) by melt blending. Both mechanical and rheological properties of the PVC blends were investigated. The submicroscopic morphology of the blends was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrate that when the weight ratio of CPE to CPP is about 6 : 1, a sample with the best impact strength and without obvious decline in tensile strength can be obtained. The impact strength correlates well with SEM morphologies, and TEM micrographs in the necking of the tensile specimen indicate that a cold‐drawing deformation of rigid particles happens as reported by T. Kurauchi and T. Ohta (J Mater Sci 1984, 19, 1699). Therefore, a conclusion can be drawn that CPP particles acting similar to elastic particles can toughen PVC, and the cold‐drawing deformation is the primary reason for toughening the PVC blends. In addition, the addition of CPP can promote the processibility of PVC ternary blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2478–2483, 2003     

Effect of poly(epichlorohydrin) on the thermal and mechanical properties of poly(vinyl chloride)

Five kinds of polyepichlorohydrin (PECH) of different molecular weights were synthesized and characterized by gel permeation chromatography (GPC). Mechanical blending was used to mix PECH and poly(vinyl chloride) (PVC) together. The blends of different PVC/PECH ratios were characterized by thermogravimetric analysis (TGA), tensile tests, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). TGA results show the thermal stability of PVC/PECH blends is desirable. Tensile tests indicate elongation at break is raised by increasing both the amount and the molecular weight of PECH. DSC is used to determine the glass transition temperature of PECH, and a quite low T_g is obtained. DMA results indicate that PECH has a perfect compatibility with PVC, when PECH concentration is below 20 wt %. There is only one peak in each tan δ curve, and the corresponding T_g decreases as PECH amount increases. However, above 20 wt %, phase separation takes place. The molecular weight of PECH also has a great influence on the glass transition temperature of the blends. This study shows that PECH is an excellent plasticizer for PVC, and one can tailor the glass transition temperature and tensile properties by changing the amount and the molecular weight of PECH. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Blends of plasticized poly(vinyl chloride) and waste flexible poly(vinyl chloride) with waste nitrile rubber powder

Blends of poly(vinyl chloride) (PVC) with varying contents of plasticizer and finely ground powder of waste nitrile rubber rollers were prepared over a wide range of rubber contents through high‐temperature blending. The effects of rubber and plasticizer (dioctyl phthalate) content on the tensile strength, percentage elongation, impact properties, hardness, abrasion resistance, flexural crack resistance, limiting oxygen index (LOI), electrical properties, and breakdown voltage were studied. The percentage elongation, flexural crack resistance, and impact strength of blends increased considerably over those of PVC. The waste rubber had a plasticizing effect. Blends of waste plasticized PVC and waste nitrile rubber showed promising properties. The electrical properties and LOI decreased with increasing rubber and plasticizer content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1552–1558, 2004     

Thermal stability of poly(vinyl chloride)/layered double hydroxide nanocomposites

Effects of nanoscale dispersed layered double hydroxides (LDHs) on thermal stability of poly(vinyl chloride) (PVC) in thermal and thermooxidative degradation processes are investigated by dynamic and isothermal thermogravimetric analysis (TGA), discoloration test, fourier transform infrared (FTIR), and ultraviolet‐visible (UV‐vis) spectroscopic techniques. During both stages of thermal degradation, the degradation temperatures, including onset degradation temperature and temperature of the maximum degradation rate, increase, and the final residue yield of the PVC/LDH nanocomposites reaches 14.7 wt %, more than double that for neat PVC. The thermooxidative degradation process is more complex. During the first two stages, the presence of nanoscale dispersed LDH particles enhances the thermal stability, whereas in the last stage accelerates the thermal degradation possibly due to the accumulation of heat released. Additionally, the studies of the isothermal thermooxidative degradation process by FTIR and UV‐vis spectra indicate that both polyene backbone formation and some carbonyl groups are simultaneously developed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Evaluation of the effects of biobased plasticizers on the thermal and mechanical properties of poly(vinyl chloride)

Blends were prepared of poly(vinyl chloride) (PVC) with four different plasticizers; esters of aconitic, citric, and phthalic acids; and other ingredients used in commercial flexible PVC products. The thermal and mechanical properties of the fresh products and of the products after 6 months of aging were measured. Young's modulus of the PVC blends was reduced about 10‐fold by an increase in the plasticizer level from 15 to 30 phr from the semirigid to the flexible range according to the ASTM classification, but a 40‐phr level was required for PVC to retain its flexibility beyond 6 months. At the 40‐phr level, tributyl aconitate performed better than diisononyl phthalate (DINP) or tributyl citrate, in terms of lowering Young's modulus, both in the fresh materials and those aged for 6 months. The effects of the four plasticizers on the glass‐transition temperature (T_g) were similar, with T_g close to ambient temperature at the 30‐ and 40‐phr levels in freshly prepared samples and at 40–60°C in those aged for 6 months. The thermal stability of the PVC plasticized with DINP was superior among the group. Overall, tributyl aconitate appeared to be a good candidate for use in consumer products where the alleged toxicity of DINP may be an issue. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1366–1373, 2006     

Effect of poly(vinyl chloride) resin type in the preparation process of slush powder

During the preparation of the poly(vinyl chloride) (PVC) slush powder, we found that PVC resins obtained by different polymerization methods affected many properties of slush powder and its products. Two types of commercial PVC resins were used for slush powder preparation: mass poly(vinyl chloride) (M‐PVC) and suspension poly(vinyl chloride) (S‐PVC). We used the Haake rheomix test to characterize the absorption of plasticizers into PVC resins, and the results showed that M‐PVC absorbed the plasticizers more quickly than S‐PVC. The fusion behavior of the two slush powders was studied by the thermal plate test and Haake rheomix test, and the results showed that the slush powder of M‐PVC was easier to fuse than that of S‐PVC. The different properties of the two resins and slush powder could be explained by the morphology, average size, and size distribution. Due to the “skin” of the particles' surfaces, the wider size distribution, and the large size of particles, S‐PVC absorbed the plasticizers more slowly and was more difficult to fuse. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3331–3335, 2002     

Soiling of plasticized poly(vinyl chloride)

The effects of three plasticizers and two plasticizer concentrations on the topography and soiling of poly (vinyl chloride) (PVC) were studied. Palmitic acid and triolein were chosen to represent solid and liquid soils. The feasibility of using infrared spectroscopy to quantify the amount of soil on PVC was examined. The structure of the solid model soil on plasticized PVC was studied with optical microscopy and atomic force microscopy. Palmitic acid formed two different structures on the PVC surface. Both the type and concentration of the plasticizer influenced the structure of the oily soil on plasticized PVC. The wetting of plasticized PVC with the liquid oily soil was compared to wetting with water through the measurement of the contact angles. Plasticized PVC was hydrophobic and oleophilic. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of plasticizers on mechanical,electrical, permanence,and thermal properties of poly(vinyl chloride)

Effects of three different plasticizers and their blends with dioctyl phthalate (DOP) on thermal stability, flammability, mechanical, electrical, and permanence properties of poly(vinyl chloride) (PVC) compound were studied. Various plasticizers used were DOP, butyl benzyl phthalate (BBP), isodecyl diphenyl phosphate (IDDP), and polybutylene adipate (PBA) at concentrations of up to 40 phr level. Studies showed that processability and softness were improved by addition of BBP. An increase in the content of IDDP increased the electrical and flammability properties, whereas compositions with PBA exhibited the best permanence properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3278–3284, 2003     

Preparation and structural characterization of nanocrystalline poly(vinyl chloride)

This article describes the development of novel nanocrystalline poly(vinyl chloride) (PVC) for potential applications in PVC processes and reports improvements in the mechanical properties and thermal resistance. Before the preparation of nanocrystalline PVC via jet milling, PVC was spray‐treated and heat‐treated to improve its crystallinity. The pulverization and degradation, morphology, crystalline structure, and melting‐point changes of postmodified PVC during jet milling and the relationship between the distributions of the particle size and processing temperature were investigated. X‐ray analysis and density testing indicated increased density and improved crystallinity. The crystalline region of nanocrystalline PVC was less than 80 nm, with a particle size distribution of 5–20 μm and a melting point of less than 128°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 563–569, 2004     

Influences of individual and composed poly(vinyl alcohol) suspending agents on particle morphology of suspension poly(vinyl chloride) resin

Effects of individual and composed poly(vinyl alcohol) (PVA) suspending agents on the particle morphology of poly(vinyl chloride) (PVC) resins were investigated and discussed in the view of PVA absorption at the oil/water interface and interfacial behavior. It was shown that the percentage and surface coverage of PVA at the oil/water interface decreased with the increase of the degree of hydrolysis (DH) of PVA in the DH range of 70–98 mol %, while the interfacial tension of VC/PVA aqueous solution increased linearly with the increase of DH of PVA. PVC resin with more regular particle shape, increased agglomeration and fusion of primary particles, lower porosity and higher bulk density, was prepared by using PVA with a higher DH as a suspending agent. This was caused by the occurrence of drop coalescence at the very early stage of VC polymerization, the increase of particle shrinkage, and the lower colloidal protection to primary particles. It was also shown that the interfacial tension of VC/water in the presence of composed PVA suspending agents varied linearly with the weight composition of the composed PVA suspending agents. The particle properties of PVC resin prepared by using the composed PVC suspending agents were usually situated in between the properties of PVC resins prepared by using the corresponding individual PVA suspending agent. The particle morphology and properties of PVC resin could be controlled by the suitable choice of the composed PVA suspending agents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3848–3855, 2003     

Chemical recycling of poly(vinyl chloride): Application of partially dehydrochlorinated poly(vinyl chloride) for producing a chemically modified polymer

Poly(vinyl chloride) (PVC) pipes were chemically modified to produce a sulfonated polymer with dehydrochlorinated PVC samples as intermediates. Two intermediates were formed: (1) partially dehydrochlorinated PVC with long sequences of conjugated double bonds and (2) the product of the partial dehydrochlorination of PVC and the nucleophilic substitution of chlorine by hydroxyl groups. The IR spectra showed that the dehydrochlorinated samples were heterogeneous materials, showing different proportions of elimination products, hydroxyl substitution, and partial oxidation. Samples dehydrochlorinated with poly(ethylene glycol) with a molecular weight of 400 g/mol for 24 h and 15 min showed the highest sulfonation yield, which was related to the sulfonation mechanism occurring predominantly because of the presence of hydroxyl groups in a mixture of vinyl alcohol and vinyl chloride units. The sulfonation was confirmed by the presence of a medium‐intensity band at 1180 cm^?1, assigned to sulfonic groups. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of chlorinated poly(vinyl chloride)‐g‐poly(N‐vinyl‐2‐pyrrolidinone) membranes and their water permeation properties

Chlorinated poly(vinyl chloride) (CPVC) membranes for microfiltration processes were prepared with the combined process of a solvent evaporation technique and the water‐vapor induced‐phase‐inversion method. CPVC membranes with a mean pore size of 0.7 μm were very hydrophobic. These membranes were subjected to surface modification by ultraviolet (UV)‐assisted graft polymerization with N‐vinyl‐2‐pyrrolidinone (NVP) to increase their surface wettability and decrease their adsorptive fouling. The grafting yields of the modified membranes were controlled by alteration of UV irradiation time and NVP monomer concentration. The changes in chemical structure between the CPVC membrane and the CPVC‐g‐poly(N‐vinyl‐2‐pyrrolidinone) membrane and the variation of the topologies of the modified PVC membranes were characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, and field emission scanning electron microscopy. According to the results, the graft yield of the modified CPVC membrane reached a maximum at 5 min of UV exposure time and 20 vol % NVP concentration. The filtration behavior of these membranes was investigated with deionized water by a crossflow filtration measurement. The surface hydrophilicity and roughness were easily changed by the grafting of NVP on the surface of the CPVC membrane through a simultaneous irradiation grafting method by UV irradiation. To confirm the effect of grafting for filtration, we compared the unmodified and modified CPVC membranes with respect to their deionized water permeation by using crossflow filtration methods. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3188–3195, 2003     

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     

Effect of hydrotalcite on the thermal stability,mechanical properties,rheology and flame retardance of poly(vinyl chloride)

Compounds of poly(vinyl chloride) (PVC) and hydrotalcite were prepared via melt blending, and the thermal stability, mechanical properties, rheology and flame retardance were studied. Transmission electron microscopy showed that the hydrotalcite achieved an optimal dispersion in PVC compounds when surface‐treated with titanate coupling agent. The Congo Red test and thermogravimetric analysis demonstrated that the thermal stability of PVC was improved significantly only in the presence of a complex of the hydrotalcite and the organotin stabilizer. Such a significantly positive thermal stabilizing effect was attributable to the stabilizing mechanisms that the electrostatic interaction generated between the electron cloud of chlorine atoms in PVC chain and the positive lay charge of hydrotalcite, which resulted in a decrease in electronic cloud density of chlorine atoms. This weakened the activity of chloride atoms, and restricted the initiation of the dehydrochlorination. A surface treatment for the hydrotalcite with the titanate coupling agent could reduce deterioration of the mechanical and rheological properties of the PVC at low concentration of hydrotalcite. The hydrotalcite also enabled useful application of PVC as a flame retardant as well as a smoke retarder in the light of a LOI value of more than 28.7 and UL 94 V‐0 grade at a PVC/hydrotalcite weight ratio of 70/30. Copyright © 2004 Society of Chemical Industry