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     

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

Phthalates can be replaced by other harmless and environmentally friendly plasticizers, such as isosorbide diesters (ISB), and epoxidized sunflower oil (ESO), which has been proved an efficient stabilizer for poly (vinyl chloride) (PVC) in helping to prevent degradation during processing. Formulations based on PVC with different amounts of ISB, ESO, and di‐(2‐ethylhexyl) phthalate (DEHP) from 0 to 60 parts by weight per hundred parts of resin were realized. To make PVC flexible with partial amounts of the debated phthalates as plasticizers, we use a combination of DEHP, ISB, and ESO. Effects of these two biobased plasticizers, ISB and ESO, and their mixture with DEHP on thermal stability by measuring discoloration degrees and thermal gravimetric analysis, on mechanical properties such tensile strength, elongation at break, and hardness, were characterized. Plasticizer permanence properties of PVC compounds were studied. Studies showed that processibility and flexibility were improved by the addition of a plasticizer system (ISB, ESO, and DEHP). An increase in the content of ISB and/or ESO increased thermal and mechanical properties, whereas compositions with ternary compositions of ISB/ESO/DEHP (15/15/30) exhibited the best performance properties. J. VINYL ADDIT. TECHNOL., 20:260–267, 2014. © 2014 Society of Plastics Engineers     

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     

Effect of stabilizer type on the mechanical properties of rigid poly(vinyl chloride). I

The effect of stabilizers on the mechanical properties of UPVC and how these are affected by different formulations has been studied. Three stabilizers, tin mercaptide MT, lead system Pb, and Ba/Cd/Zn complex BCZ, were used. A high -intensity blender was used for dry blend compounding, and the blend was injection -molded on a Kuasy single Screw injection molding machine. A two -cavity mold was made for forming the specimens. The specimens were tested for their impact strength, fracture toughness, tensile strength, and flexural strength. Increasing MT stabilizer was shown to increase the tensile strength and to decrease fracture toughness, impact strength, and ductility; this was attributed to antiplasticization. Increasing the Pb stabilizer conferred ductility and improved fracture toughness and impact strength. It is concluded that stabilizers have a marked effect on the mechanical behavior of rigid PVC.     

Anomalous dynamic mechanical behavior of poly(vinyl chloride)

In this paper, we present a study of the dynamic mechanicall behavior of a quenched poly(vinyl chloride). A new relaxation between the glass transition and the β transition is reported. We have related this new relaxation to an absence of physical aging.     

Fusion,electrical conductivity,thermal, and mechanical properties of rigid poly(vinyl chloride) (PVC)/carbon black (CB) composites

Rigid and conductive poly(vinyl chloride) (PVC)/carbon black (CB) composites were prepared in a Haake torque rheometer. The results illustrate that the fusion torque of the PVC/CB composite is increased as the amount of CB is increased. Both the fusion percolation threshold and the fusion time of PVC/CB composites are decreased when the amount of CB is increased. Two major weight loss stages are observed in the TGA curve of PVC/CB composite. The first thermal degradation onset temperature (T_onset1) of PVC/CB composite is decreased as the amount of CB is increased. Both the first and second weight loss stages (ΔY₁ and ΔY₂) of PVC/CB composites are decreased as the amount of CB is increased. The surface resistivity of PVC/CB composite remains almost constant up to 6 parts per hundred unit weight of resin (phr) CB. When the amount of CB in PVC/CB composite is increased from 6 to 15 phr, the surface resistivity of PVC/CB composite is dramatically decreased from 10¹⁰ Ω/sq to 10⁴ Ω/sq. Because of the addition of CB, the rigidity of PVC/CB composite is increased and thus the mechanical properties, such as yield strength, tensile strength, and the Young's modulus, are improved. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

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     

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.     

Correlation between some solution and mechanical properties of poly(vinyl chloride) and chlorinated poly(vinyl chloride)

Correlations have been found between solubility parameters and some mechanical properties of a series of vinyl polymers containing 56.6–69.9% chlorine when tested below their glass transition temperature. It is shown that stress at yield increases similarly with chlorine content and with the volume occupied by a monomer unit in the polymer. Using the Reiner-Weissenberg theory of the dynamic strength of materials as a criterion and a rheological model based on a pair of Maxwell bodies in parallel with a Hooke spring, the amount of dissipated and conserved work to yield point was calculated. A parameter, defined as the ratio of work to cohesive energy density, describes the efficiency of the system. The overall efficiency of the system, based on work to break, and proportional efficiency, based on work to yield point, are affected by chlorine content and strain rate. In addition, a potential energy parameter is defined which describes the cohesive energy per volume occupied by monomer unit of the polymer. This parameter is proportional to the total work to break as well as to the ratio of the residual work after yield to total work at all strain rates tested. The major portion of work is conserved up to yield; only a small portion is dissipated. From the yield point to break, after the onset of viscous flow, the major part of this work is dissipated.     

Viscoelastic properties,morphology, and thermal stability of rigid and plasticized poly(vinyl chloride)/poly(methyl methacrylate) blends

Viscoelastic properties, morphology, and thermal stability of rigid and plasticized poly(vinyl chloride)/poly (methyl methacrylate) (PVC/PMMA) blends were studied. For that purpose, blends of variable composition from 0 to 100 wt% were prepared in the presence (15, 30, and 50 wt%) and in the absence of di(2‐ethylhexyl) phthalate as plasticizer. Their miscibility was investigated by using dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). The DMTA and SEM results showed that the two polymers are miscible. Thermogravimetric studies on these blends were carried out in a flowing atmosphere of air from ambient temperature to 550°C. The results showed that the thermal degradation of rigid and plasticized PVC/PMMA in this broad range of temperature is a three‐step process and that PMMA exerted a stabilizing effect on the thermal degradation of PVC during the first step by reducing the rate of dehydrochlorination. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Rheological and mechanical properties of plasticized poly(vinyl chloride)

The dependence of rheological properties of a plasticized, filled poly(vinyl chloride) compound on three different methods of thermomechanical treatments has been studied. These three different states of the compound are the dry blend mixed at a maximum temperature of 93°C, the two-roll milled sample prepared at 150°C from the dry blend and the molded sample pressed at 170°C from the previously milled material. At 150°C the viscosity and elasticity of the molded sample are considerably higher than those of the dry blend and the milled sample. At higher temperatures, although their flow curves more or less merge, extrudate swell, extrudate appearance and extrudate tensile properties of the three samples vary. The mechanical and Theological properties of the quenched and annealed molded samples and those of the same compound without filler have also been investigated.     

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 crosslinking on the mechanical and thermal properties of poly(vinyl alcohol)

Poly(vinyl alcohol) was crosslinked with hexamethylene diisocyanate in solution. A broad range of degrees of crosslinking, from 1.7 up to 74 mol% of reacted hydroxyl groups, was achieved. The variation of the thermal and mechanical properties of PVA with the crosslinking density show an initial decrease due to the diminution of the crystallinity of the system, caused by the crosslinking. After an abrupt rise at about 20%, the properties tend to level off independently on the increase of the crosslinking. This behaviour is explained as a result of the competitive action of at least three factors during the crosslinking: (i) weakening of the existing physical network due to hydrogen bonding; (ii) formation of a chemical network; and (iii) introduction of flexible moieties. The last factor is closely connected with the specific chemical structure of the crosslinker itself.     

Effect of lignin esters on improving the thermal properties of poly(vinyl chloride)

To improve the thermal stability of poly(vinyl chloride) (PVC) and the utilization of lignin (L), different L esters were added to PVC to produce the plates with enhanced thermal stabilities. The properties and structures of the L ester–PVC plates and the properties of the L esters and their mixtures with PVC were analyzed by universal mechanical testing, static thermal stability testing, thermogravimetry–Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, FTIR spectroscopy, scanning electron microscopy, and differential scanning calorimetry. The results show that L improved the thermal stability of PVC, but the mechanical properties were substantially deteriorated. Proper esterification of L improved the thermal stabilities and mechanical properties of the plates. Noncyclic anhydride acetylated L–PVC plates possessed good static and dynamic thermal stabilities and mechanical properties. The PVC plates incorporated with the L esters with a degree of esterification of around 40% exhibited the best combination properties. Maleated L–PVC plates had good dynamic thermal stability and mechanical properties but poor static thermal stability. The opposite properties were found for succinylated L–PVC plates. The differences in the properties of different L ester–PVC plates were attributed to the different abilities of L esters to capture free radicals, the crosslinking reaction between L esters and PVC, and their compatibility. Different properties of the L esters indicated their different applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47176.     

Effect of precipitated calcium carbonate on the mechanical properties of poly(vinyl chloride)

This study examines the effect of various grades of precipitated and ground calcium carbonate on the tensile strength and Charpy impact energy of extruded PVC profile. The results confirm that ultra‐fine precipitated calcium carbonate (pcc) can give rise to large improvements in single notch impact strengths. Control values of 9 kJ/m^?2 were increased to 79 kJ/m^?2 through the addition of ultra‐fine pcc. The results have been interpreted in terms of the particle size, shape, and coating of the calcium carbonate grades and the effect on the gelation characteristics of the PVC formulations. J. VINYL ADDIT. TECHNOL., 13:98–102, 2007. © 2007 Society of Plastics Engineers.     

Ductile fracture of rigid poly(vinyl chloride)

The fracture processes which take place in rigid poly(vinyl chloride) have been investigated. Under tension, crazes are formed and when necking occurs they pass almost unaltered through the neck. The crazes have the fibrillar structure generally observed with other plastics. After necking, fracture occurs either by the propagation of a crack from the edge of the test-piece or by the formation of a diamond-shaped cavity which initiates from a surface craze. The characteristic form of the diamond-shaped cavity appears to be controlled by the yield behaviour of the deformed polymer. At low temperatures (?40°C) it is possible to apply the methods of fracture mechanics to notched specimens and a value of 1·05 × 10^?3MN/m is obtained for the energy of formation of a new surface in undrawn material.     

Epoxylsilane crosslinking of rigid poly(vinyl chloride)

Crosslinking is an effective way to improve the qualities of poly(vinyl chloride). A crosslinking system consisting of R‐glycidoxypropyltrimethoxysilane (KH560) has been first used to introduce crosslinking into rigid poly(vinyl chloride). Different thermal stabilizers (organotin, Ca/Zn stearate, and Ba/Zn stearate) as well as sodium bisulfite additive were tried to promote the grafting of epoxyl group and enhance the degree of crosslinking. FTIR spectra showed that grafting and crosslinking of KH560 with poly(vinyl chloride) could take place, and a gel content of 40% could be obtained when more than 10 phr epoxylsilanes were used in the condition of 2 : 1 (parts by weight) ratio of BaSt₂/ZnSt₂ and 1 : 1M ratio of NaHSO₃/KH560, while the premature crosslinking was avoided. Thermal properties had been studied. The results showed that the Vicat softening temperature of crosslinked PVC could be improved about 10°C when 5 phr epoxylsilane was added, and thermal degradation could be delayed with increase in gel content. Therefore, epoxylsilane‐crosslinked PVC will have the potential for extensive applications © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Dynamic mechanical studies of thermal aging in poly(vinyl chloride)

The effects of thermal aging on the dynamic mechanical properties of rigid poly(vinyl chloride) (PVC) and chlorinated poly(vinyl chloride) (CPVC) are examined in the glass transition (T_g) and β transition (T_β) regions. PVC, when quenched through T_g and then annealed at 40°C, exhibits a sub-T_g peak in the loss modulus function. The position of the peak moves to higher temperatures with increasing annealing time. The effect is analogous to sub-T_g endothermic peaks previously observed by differential scanning calorimetry (DSC). A sub-T_β peak in the tan δ or the loss modulus functions can be produced by quenching through T_β. The effect of heating rate on the sub-T_β peak is explored.     

Preparation of poly(p-phenylene terephthalamide)/poly(vinyl chloride) molecular composite and its thermal and mechanical properties

Poly(p-phenylene terephthalamide) (PPTA) was blended with poly(vinyl chloride) (PVC) by solution-blending method. PPTA was metalated for dissolving in dimethyl sulfoxide. Dimethyl sulfoxide was used as a common solvent. In PPTA/PVC composite, PPTA accelerated the thermal degradation of PVC. PPTA molecules are aggregated as microfibrillar form in PVC matrix. Such microfibrils are dispersed homogeneously in PVC matrix, according to polarizing microscopic observation. The average diameter of the microfibrils becomes smaller in the composite with lower content of PPTA. In the surface region of PPTA microfibrils the intermolecular hydrogen bonds between C? Cl of PVC and N? H of PPTA are formed. Young's modulus and the yield stress at room temperature were higher in the composites than those in PVC. The modulus of the composites was higher, especially at the high temperatures above their glass transition temperatures, than that in PVC. The temperature dependence of modulus can be calculated by using the mechanical model equivalent to the quasi-3-dimensional microfibrillar model which will be approximately applied to the composite structure. It becomes apparent that the modulus of the PPTA microfibrils evaluated by using the mechanical model is higher in the higher molecular weight PPTA.