Rheology of poly(vinyl chloride) plastisol: Effect of a particular nonionic cosurfactant

The rheology of poly(vinyl chloride) plastisols is affected by many aspects of the formulations, such as type and concentration of each component, temperature and, perhaps most important, the polymer properties. Taking into consideration the surfactants normally present during the polymerization reaction, in this work, a different approach was followed. Besides the usual polymerization surfactants, a particular ester‐type emulsifier was also added in a postpolymerization stage. The results show a particle aggregation effect in the initial aqueous dispersion (latex) that promotes a significant decrease in the viscosity level, aging profile, and different viscoelastic properties of the latter plastisols. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and application of a natural plasticizer based on cardanol for poly(vinyl chloride)

A natural plasticizer with multifunctional groups, similar in structure to phthalates, cardanol derivatives glycidyl ether (CGE) was synthesized from cardanol by a two‐step modification process and characterized by FT‐IR, ¹HNMR, and ¹³CNMR. The resulting product was incorporated to PVC (CGE/PVC), and plasticizing effect was compared with PVC incorporated with two kinds of commercial phthalate ester plasticizers bis (2‐ethylhexyl) benzene‐1,4‐dicarboxylate (DOTP) and diisononyl phthalate (DINP). Dynamic mechanical analysis and mechanical properties testing of the plasticized PVC samples were performed in order to evaluate their flexibility, compatibility, and plasticizing efficiency. SEM was employed to produce fractured surface morphology. Thermogravimetric analysis and discoloration tests were used to characterize the thermal stabilities. Dynamic stability analysis was used to test the processability of formulations. Compared with DOTP and DINP plasticized samples, CGE/PVC has a maximum decrease of 9.27% in glass transition temperature (T_g), a maximum increase of 17.6% in the elongation at break, and a maximum increase of 31.59°C and 25.31 min in 50% weight loss (T50) and dynamic stability time, respectively. The obtained CGE also has slightly lower volatility resistance and higher exudation resistance than that of DOTP and DINP. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42465.     

The effect of the plasticizer system on the processability of poly(vinyl chloride) compounds

To conserve energy and process time, the judicious use of benzyl phthalate as a partial substitution for dialkyl phthalate is suggested. Data is presented from laboratory and pilot plant tests. Confirmation and correlation with factory trials is shown.     

Migration resistant polymeric plasticizer for poly(vinyl chloride)

Flexible films of poly(vinyl chloride) (PVC) and linear or branched poly(butylene adipate) (PBA), synthesized from 1,4‐butanediol and adipic acid or dimethyl ester of adipic acid, were aged in an aqueous environment for 10 weeks to study how branching, molar mass, and end‐group functionality affect the leaching of polyester plasticizer from thin films. Principal component analysis was applied to reveal patterns and correlations between mechanical properties, material characteristics, and aging behavior. Introduction of branches in the polyester structure increased the miscibility between PVC and the polyester, resulting in improved mechanical properties and lower water absorption. Methyl ester end‐group in PBA polyester stabilized the polymeric plasticizer toward hydrolysis, and reduced the formation and migration of monomeric degradation products from the blends during aging in water. The combination of branched structure with methyl ester end‐groups resulted in a migration resistant polymeric plasticizer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2458–2467, 2007     

Dielectric and electromechanical studies of plasticized poly(vinyl chloride) fabricated from plastisol

Poly(vinyl chloride) (PVC) plastisol is used in many industrial applications and is considered an electrically inactive material. To explore the potential of plastisol as an electroactive material, the dielectric properties, space charge distribution, mechanical properties, internal structure and electromechanical behavior of plasticized PVC (PVC gel) prepared from plastisol by heating were investigated. The gel exhibited a large dielectric constant at low frequencies (1–1000 Hz), an asymmetric charge distribution and excellent mechanical properties. Various DC electric fields were applied to the gel placed parallel between two electrodes and the electrostatic adhesive force to the anode was measured. The results of small‐ and wide‐angle X‐ray scattering suggested that the electromechanical properties of the gel originated from the characteristics of the physical crosslinking distance (ca 20 nm) of PVC in the gel structure. Considering the dielectric properties, space charge density and adhesion force to the anode, PVC gels prepared from plastisol using the heating method have potential for use as electroactive materials. © 2013 Society of Chemical Industry     

Alloying of poly(vinyl chloride) to reduce plasticizer migration

Concern over the migration of low molecular weight plasticizer from flexible poly(vinyl chloride) (PVC) used in toys and medical products has spearheaded the commercialization of a number of plasticizing polymers. In this study the plasticizing behavior of an ethylene/vinyl acetate/carbon monoxide terpolymer (Elvaloy® from DuPont) was investigated. Blends of PVC, Elvaloy 742, and dioctyl phthalate (DOP) were processed on a twin‐roll mill and compression molded into plaques. These materials were characterized in terms of their hardness, glass‐transition temperature (T_g), clarity, mechanical properties, and plasticizer migration behavior. The ratios of PVC/DOP/Elvaloy investigated were determined by experimental design. Using this approach it was possible to model the results and produce contour plots to map out the properties of a wide range of formulations. It was confirmed that Elvaloy 742 is compatible with PVC and has a plasticizing effect: this was demonstrated both in terms of a reduction in Shore A hardness and a reduction in T_g. Plasticizer migration was reduced in proportion to the amount of liquid plasticizer replaced. Plasticizing with Elvaloy gave an improvement in tear strength. However, at constant hardness there was no improvement in tensile strength from replacing DOP with Elvaloy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2022–2031, 2004     

Polycaprolactone as a permanent plasticizer for poly(vinyl chloride)

Polycaprolactone at moderate usage levels has been determined to provide desirable modifications of both rigid and plasticized poly(vinyl chloride). In rigid PVC it effected significant improvement in melt processing as well as good modulus, tensile strength, and kerosene resistance. Impact strength was not measurably altered, but heat-distortion temperature was appreciably lowered. In flexible PVC, polycaprolactone contributed increased tensile strength and ultimate elongation, reduced volatility, and kerosene extraction. Lowering of modulus and flex temperatures were similar to conventional liquid polymeric plasticizers, but melt processability was not as good as lower-molecular-weight plasticizers.     

The effect of fusion and physical aging on the toughness of poly(vinyl chloride)

It is well known that during aging or annealing, materials become stiffer and more brittle, and creep and stress relaxation rates decrease. Research in this area is very important because physical aging (annealing) plays a large role in the production of products, and it also occurs during the use of the objects or products. The decrease of free volume with time is unavoidable even at ambient temperatures. The influence of fusion and physical aging on the toughness of extruded PVC profiles was investigated. It is known that the toughness of PVC is influenced by secondary crystallization—after primary particles of PVC are partially melted. Recrystallization upon cooling or annealing forms a three-dimensional structure tying together the primary particles. This three-dimensional structure normally produces a tougher PVC product. The density of glassy PVC can be changed by changing the quenching rate. The density can be further changed by annealing below T_g. The densification of a glassy polymer normally leads to a less tough PVC product. This study uses density measurements and differential scanning calorimetry scans to measure the amount of enthalpy relaxation (related to densification) and crystalline melting energy (related to the amount of crystallinity) for various annealed samples. These are related to toughness as measured by notched Izod and droppeddart impact tests.     

Influence of temperature on the ultrasonic degradation of poly(vinyl acetate) and poly(vinyl chloride)

This study investigates the effect of temperature on the ultrasonic degradation of polyvinyl acetate and polyvinyl chloride in chlorobenzene. The time evolution of molecular weight distribution was determined using gel permeation chromatography. Continuous distribution kinetics was used to obtain the degradation rate coefficients. The rate coefficients decrease with increasing temperature, and this is attributed to the increase of vapor pressure and the decrease of kinematic viscosity. The degradation rate coefficient also changes sharply near the glass transition temperature, indicating that this factor may play a role in the degradation process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2818–2822, 2003     

Montmorillonite clay/poly(methyl methacrylate) hybrid resin and its barrier property to the plasticizer within poly(vinyl chloride) composite

A poly(methyl methacrylate) (PMMA)‐clay hybrid resin was prepared via bulk polymerization methyl methacrylate monomer in the presence of montmorillonite intercalated with an ammonium salt of dctadecylamine. The products were characterized by infrared spectroscopy, X‐ray diffraction, pyrolysis gas chromatography, and transmission electron microscopy. Results confirm that the resin is intercalated with PMMA molecules. The layer spacing of montmorillonite are enlarged, whereas the silicate layers are homogeneously dispersed individually. When the PMMA‐clay hybrid was blended with plasticized poly(vinyl chloride), the resulting composite exhibited excellent barrier property in preventing the plastizer's migration from the inner matrix to the surface of the product. This is presumably caused by barrier property of the silicate layers dispersed in the composite. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 425–430, 1999     

Some aspects of plasticizer migration from poly(vinyl chloride) sheets

Long-term migration data, by radioactivity measurements, are presented for the systems poly(vinyl chloride) (PVC)/labelled dioctyl phthalate (DOP)/methanol, n-propanol, or n-butanol. At equilibrium, migration levels determined exceed 85% for methanol and reveal complete removal for the higher alcohols. Migration kinetics failed to be described by the long-term Fickian approximation with a diffusion coefficient independent of concentration. Nevertheless, q_t/q_∫, where q_∫ the amount migrated at infinite time and q_t the amount lost up to time t, increases linearly with (time)^1/2/(thickness) during the initial stages of the process and then a linear also relationship appears, but with severely reduced slope. Similar data concerning the systems PVC/DOP/petroleum oils confirm the behavior observed.     

Effect of concentration and type of plasticizer on some physical properties of poly(vinyl chloride)

The effect of four different types and concentrations of plasticizers on some physical properties of poly(vinyl chloride) (PVC) has been studied. DOP, DOA, TTP, and Hex were used as plasticizers in concentration levels of up to 24% of PVC weight. The plasticized and unplasticized PVC were processed into sheets by compression molding. The sheets were tested for their vicat softening point, shore D hardness, flexural properties, and dynamic fatigue. It was found that the vicat softening point, shore D hardness, flexural yield strength, and flexural modulus decrease with increase in plasticizer concentration, though in some cases a threshold concentration must be passed before these effects can be observed. Close similarities were always found in the behavior of DOP and DOA and also between TTP and Hex. It was found in the study of flexural fatigue properties of PVC plasticized by DOP that an increase in plasticizer concentration led to a decrease in load bearing ability only at stress levels above 20 MPa.     

The effect of an epoxidized plasticizer on the thermo-oxidative ageing of poly(vinyl chloride)/epoxidized natural rubber thermoplastic elastomers

The effects of an epoxidized plasticizer on the mechanical properties and thermo-oxidative ageing behaviour of poly(vinyl chloride)/epoxidized natural rubber thermoplastic elastomers (TPEs) were investigated. Aged and unaged blends were characterized by FTIR, tensile properties, tear strength, hardness and dynamic mechanical analysis (DMA). The properties of the epoxidized soya oil (ESO) plasticized TPEs were compared with those of the di-2-ethylhexylphthalate (DOP) plasticized counterparts. The presence of epoxide groups in ESO has been shown to produce two conflicting effects. On the one hand, the presence of excessive epoxide groups has resulted in poor ageing behaviour. On the other hand, it has resulted in a good interaction and compatibility with PVC/ENR. It was found that the tensile strength of the ESO plasticized blends were comparable with the DOP plasticized ones, but the elongation at break (EB) of the ESO blends fell short of that of the DOP blends. Also the retention of both tensile properties for the ESO blends was poorer than for DOP blends. Hardening and embrittlement also occurred in the ESO blends. Despite these weaknesses, ESO could be an ideal plasticizer for the PVC/ENR system as indicated by plasticizer permanence and the greater efficiency of plasticization. © 1998 SCI.     

Emissivity values for poly(vinyl chloride) with varying plasticizer compositions

The emissivity of plasticized poly(vinly chloride) (PVC) containing varying compositions and amounts of plasticizer was investigated. The four plasticizers examined were dibutyl phthalate (DBP), dioctyl phthalate (DOP), diisodecyl phthalate (DIDP) (Phthalic acid type), and dioctyl adipate (DOA) (adipic acid type). The emmissivity of plasticized PVC film increased almost equally with the difference in the compositions between DOP and DOA. It was also clear that the emissivity of the plasticized PVC film decreased gradually with the molecular sequence length of DBP, DOP, and DIDP.     

Chlorinated atactic polypropylene as a plasticizer for poly(vinyl chloride)

Atactic polypropylene, a byproduct obtained in the manufacture of isotactic polypropylene, has been chlorinated under various reaction conditions. The chlorination reaction is reasonably fast so as to give a product of 53-43% chlorine content in 3 h. The chlorinated product has been incorporated in poly(viny1 chloride) formulations with a view to study its plasticizing activity. Generally this type of compound acts only as a secondary plasticizer; hence it has been used in combination with di(2-ethylhexyl)phthdate, a primary plasticizer. Different proportions of these two plasticizers have been added to poly(vinyl chloride) resin to obtain a series of formulations. These compounds were evaluated, and it appears that the addition of chlorinated atactic polypropylene (APPC) helps in easy processing and increases the throughput. The increasing concentration of APPC showed an upward trend in die head pressure and torque indicating an increase in melt viscosity. The results of physical properties evaluation show that APPC acts as a reinforcing agent and also imparts permanence to the plasticizers.     

Preparation of novel reactive plastisol based on poly(vinyl chloride) and multifunctional acryl esters

Poly(vinyl chloride) (PVC) powder was mixed with various polyfunctional acryl monomers as plasticizers to prepare acrylate‐modified plastisols. This class of plastisol was hardened into the B stage without reaction and then cured into a harder material through crosslinking of the acrylate. The best formulation was attained after evaluation of various acrylates, PVC grades, and peroxides. Several difunctional acrylates with solubility parameters similar to that of PVC could be most conveniently used as the plasticizer. A sheet molding compound was obtained by the combination of the resultant plastisols with glass fiber by compression molding using conventional machines. It was cured into a PVC‐based fiber reinforced plastic with high performance. This class of acrylate‐modified plastisol is called reactive plastisol. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1794–1801, 2000     

Surface treatment of plasticized poly(vinyl chloride) to prevent plasticizer migration

In this investigation, plasticized poly(vinyl chloride) (PVC) was treated with poly(azido acrylate)s to prevent plasticizer migration. This was achieved by modification of PVC sheets with poly(azido acrylate)s in a dichloromethane solution followed by irradiation under UV light. The surface‐modified PVC sheets with poly (azido acrylate)s were characterized with Fourier transform infrared spectroscopy and scanning electron microscopy analyses. The migration of the plasticizer was prevented to a large extent from modified PVC in comparison with unmodified PVC. The amount of plasticizer migration with respect to the irradiation time, incubation time, and number of dipping times was evaluated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

The solubility of vinyl chloride in poly(vinyl chloride)

The solubility of vinyl chloride monomer (VCM) in PVC powders has been studied by equilibrium vapor pressure and microbalance gravimetric techniques at temperatures from 30 to 110°C. At temperatures and VCM concentrations above the glass transition, the solubility closely follows the Flory-Huggins equation with χ = 0.98 and is independent of temperature and of the PVC type, molecular weight, or history. In the glassy state, the VCM solubility is higher than the Flory-Huggins value and shows pronounced dependence upon time and the PVC history. These results have been interpreted through the dual-mode sorption concept of Michaels, Vieth, and Barrie: Normal dissolution follows the Flory-Huggins relation, and the additional glassy-state solubility represents the contribution of a hole-filling process. Changes in solubility with time and sample history parallel well-known volume relaxation processes, indicating that vapor solubility measurements offer a direct and sensitive measure of the free-volume state of glassy polymers.