Kinetic analysis of the thermal degradation of PVC plastisols

The thermal degradation of plasticized polyvinyl chloride (plastisol) is reported here. Plastisols used in the present work were prepared with the plasticizer diethylhexyl phthalate in different proportions. Thermogravimetric analysis has been applied to study the behavior of plastisols at high temperatures and to evaluate their degradation kinetics. Several tests were carried out at different heating rates and the variation of the degree of reaction with time and temperature was calculated. The influence of the heating rate in dynamic measurements (5–40°C/min) on kinetic parameters, such as activation energies and reaction orders, has also been studied. These parameters were calculated from dynamic thermogravimetric analysis tests using Friedman analysis and a kinetic model for the degradation of poly(vinyl chloride) and plastisols has been then developed. The obtained model was able to simulate the thermal degradation process of plastisols in dynamic conditions and was used to evaluate the effects of additives in the degradation. The results of this study can be used to optimize the concentration of plasticizers and stabilizers in poly(vinyl chloride) formulations. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1069–1079, 1999     

Evaluation effects of biobased plasticizer on the thermal,mechanical, dynamical mechanical properties,and permanence of plasticized PVC

Sunflower oil (SO) is a renewable resource that can be epoxidized, and the epoxidized SO has potential uses as an environmentally friendly in polymeric formulations, especially for poly (vinyl chloride) (PVC). Epoxidized sunflower oil (ESO) was prepared by treating the oil with peracetic acid generated in situ by reacting glacial acetic acid with hydrogen peroxide. Epoxidation was confirmed using spectroscopic and titration methods. ESO was used as a coplasticizer in PVC for the partial replacement of di‐(2‐ethyl hexyl) phthalate (DEHP). The effect of ESO on the thermal stability of plasticized PVC was evaluated by using synmero scale for the sheets. In presence of ESO plasticized PVC samples showed a reduction in discoloration and the number of conjugated double bonds. By using thermogravimetry, the incorporation of 15/45 of ESO/DEHP in PVC presents the lowest weight loss. The results of the shore hardness and mechanical properties showed that a proportion of DEHP could be substituted by ESO. By use of DMA, the formulation which contains 25 % wt of ESO in plasticizer system shifts the glass transition temperature (T_g) to ambient temperature. The migration phenomenon was studied on PVC based samples plasticized with DEHP and ESO in varying amounts. The migration was monitored by the weight loss percentage of the samples immersed into n‐hexane or heated in an oven. The amount of extracted or volatilized DEHP is proportional to the added ratio of ESO in plasticizer system. All of this favored the partial replacement of DEHP by ESO as biobased plasticizer for flexible PVC. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of crystallinity in the curing mechanism of PVC plastisols

The influence of the crystalline areas observed in poly(vinyl chloride) (PVC) the mechanical and thermal properties of PVC plastisols was studied. Several industrial‐degree PVC resins were used to obtain a broad range of molecular weights and processing conditions for PVC plastisols. The gelation process was fully studied at different temperatures and was related to the existence of crystalline areas at high temperatures, even near the glass transition. A simple explanation of the phenomena observed during the gelation of plasticized PVC is proposed, according to the variation in the mechanical and thermal properties at different temperatures. The final gelation was obtained at 140–150°C, which was a lower temperature than those at the beginning of the thermal degradation process. The thermodynamic aspects of the gelation of plasticized PVC were mainly controlled by the PVC resin properties, whereas the plasticizer only influenced the diffusion and stability of the material. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 538–544, 2004     

Processability and mechanical properties of commercial PVC plastisols containing low‐environmental‐impact plasticizers

Preliminary results are presented concerning the use of less‐toxic plasticizers such as dioctyl adipate (DOA) and acetyl tributyl citrate (ATBC) in plastisol formulations for rotational molding technology. The DOA and ATBC plasticizers have been studied by comparing the effects of their content, molecular architecture, and polarity on the rheological behavior of liquid plastic systems and on the mechanical properties of the ultimate products prepared with PVCs having different particle sizes and molecular‐weight distributions. Rheological tests have confirmed the differences in solvent power of the diethylhexyl phthalate (DOP), DOA, and ATBC plasticizers. The glass transition temperatures measured on rotomolded samples have shown that the use of ATBC leads to a more nearly rigid system as a consequence of the branched structure and polarity of this plasticizer when compared with DOA. Mechanical tests carried out on final products after natural and forced environmental aging revealed a slight decrease in their performance. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Characterization of resol resins modified by the addition of PVC plastisols

Plastisols, which are a blend of poly(vinyl chloride) resin and a plasticizer (DEHP), were used as a toughening agent of a resol resin in order to improve the mechanical properties. It was not possible to formulate resol blends by adding more than 10 % of plastisol owing to a lack of apparent homogeneity in the systems, which also showed many air bubbles. The relationship between dynamic mechanical, mechanical and thermal properties and the amount of plastisol added was studied. It was determined from the infrared spectroscopy and dynamic mechanical results that the resol–plastisol blends seem to be formed by a reaction between the phenol and PVC giving a higher crosslinked structure. An improvement in the thermal resistance of the blends at lower temperatures was observed with an increase in the percentage of plastisol. Flexural analysis showed the elastic behaviour of the systems. However, it was not possible to observe the effect of the plasticizer (DEHP) owing to the low quantity of plastisol that was added to the resol. Copyright © 2004 Society of Chemical Industry     

Effects of inorganic nano‐particles on plasticizers migration of flexible PVC

The influences of nano‐particles (nano‐sized CaCO₃ and nano‐sized SiO₂) on plasticizers volatility, solvent extraction stability, and exudation stability of flexible PVC were studied. The results showed that nano‐particles could reduce migration of plasticizers, thus improved the ability of anti‐migration of flexible PVC. Further more, nano‐sized SiO₂ shows excellent property than nano‐sized CaCO₃ in resistance migration of plasticizers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal and mechanical characterization of linear low‐density polyethylene/wood flour composites

A linear low‐density polyethylene (LLDPE) matrix was modified with an organic peroxide and by a reaction with maleic anhydride (MAn) and was simultaneously compounded with untreated wood flour in a twin‐screw extruder. The thermal and mechanical properties of the modified LLDPE and the resulting composites were evaluated. The degree of crystallinity was reduced in the modified LLDPE, but it increased with the addition of wood flour for the formation of the composites. Significant improvements in the tensile strength, ductility, and creep resistance were obtained for the MAn‐modified composites. This enhancement in the mechanical behavior could be attributed to an improvement in the compatibility between the filler and the matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2775–2784, 2003     

Extensional viscosity measurements and characterization of poly (vinyl chloride‐co‐vinyl acetate) plastisols and foams

The foaming of PVC‐VA [Poly (vinyl chloride‐co‐vinyl acetate)] plastisols is a complex combination of processes involving the simultaneous curing of the paste with the evolution of gases caused by the decomposition of the chemical blowing agent. The extensional viscosity is a fundamental characteristic of the material, responsible for the behavior of the system when undergoing the extensional stress produced by the released gases. Nevertheless, such changes have not been considered to the same extent as the complex viscosity evolution or the thermal processes suffered by PVC‐VA plastisols. The objective of the present work is to study the extensional viscosity of the PVC‐VA plastisols prepared with three plasticizers of similar structure, but with different curing and rheological behavior in order to investigate its influence on the quality of the foams obtained. Extensional viscosity measurements under forced prestretch conditions revealed that depending on the structure and consequently on the compatibility of the plasticizer used, each plastisol develops its properties and structure accordingly. DINCH plasticizer (Diisononyl cyclohexane‐1,2‐dicarboxylate presenting alicyclic ring) seems to be the less compatible compared with the other two studied (both presenting aromatic rings) according to its behavior during the curing and foaming processes and may not be able to withstand the pressure evolved by the released gases during the foaming process yielding foams of poorer quality. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Flame retardancy and mechanical properties of pet‐based composites containing phosphorus and boron‐based additives

Flame retardancy of poly(ethylene terephthalate), PET, was improved using different flame retardant additives such as triphenylphosphate, triphenylphosphine oxide, zinc borate, and boron phosphate (BP). Composites were prepared using a twin screw extruder and subsequently injection molded for characterization purposes. The flame retardancy of the composites was determined by the limiting oxygen index (LOI) test. Smoke emission during fire was also evaluated in terms of percent light transmittance. Thermal stability and tensile properties of PET‐based composites were compared with PET through TGA and tensile test, respectively. The LOI of the flame retardant composites increased from 21% of neat PET, up to 36% with the addition of 5% BP and 5% triphenyl phosphate to the matrix. Regarding the smoke density analysis, BP was determined as an effective smoke suppressant for PET. Enhanced tensile properties were obtained for the flame retardant PET‐based composites with respect to PET. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42016.     

Processing and mechanical properties of bio‐derived vinyl ester resin‐based composites

A “green” vinyl ester resin (GVER) is investigated for use in structural applications. The GVER was formulated using a monodisperse vinyl ester created via a novel synthetic route capable of using bio‐waste material from paper and biodiesel industries. The GVER was used either as a neat resin or as blended with a commercial vinyl ester resin. The processing viscosity and gel times are investigated. The GVER reaches a similar viscosity as the commercial resin with only half the styrene monomer content, thereby reducing the volatile organic compounds associated with manufacturing. Composites of the GVER matrix reinforced by carbon fabric were tested for their tensile and flexural properties. The mechanical performance of the GVER compares favorably with commercial resin and provide a route for composites manufacturing from sustainably sourced vinyl ester matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44642.     

Epoxidized vegetable oil and bio‐based materials as PVC plasticizer

Phthalate esters received a considerable attention owing to its various applications and the harmful health effects resulting from phthalate exposure; thus, finding an alternative to phthalate derivatives became a necessity. Phthalate esters are commonly used as plasticizer in polymer formulation; in particular for poly(vinyl chloride) (PVC) formulation. According to the researches in the last 18 years, epoxidized vegetable oils are one of the alternatives that are strongly encouraged to substitute phthalate esters since they were proven to be valid in various applications, eco‐friendly and sustainable resource. However, most of the production practices for epoxidized vegetable oil are via conventional epoxidation that concentrates on a catalyst that is homogeneous and non‐reusable. This type of catalyst, however, causes several problems later in the process. Therefore, the selective epoxidation of vegetable oils process requires new catalytic systems that are more aligned with the green chemistry principles. This article reviews the harmful health effects associated with the exposure to phthalate esters products, explains the usage of oleochemicals resources as a substitute to phthalate esters and describes different approaches for the epoxidation of vegetable oils. Finally, it draws attention to the usage of epoxy and bio‐based compounds as plasticizers in PVC manufacturing. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46270.     

PMMA‐grafted‐silica/PVC nanocomposites: Mechanical performance and barrier properties

Poly(vinyl chloride) (PVC)/SiO₂ nanocomposites were prepared via melt mixture using a twin‐screw mixing method. To improve the dispersion degree of the nanoparticles and endow the compatibility between polymeric matrix and nanosilica, SiO₂ surface was grafted with polymethyl methacrylate (PMMA). The interfacial adhesion was enhanced with filling the resulting PMMA‐grafted‐SiO₂ hybrid nanoparticles characterized by scanning electron microscopy. Both storage modulus and glass transition temperature of prepared nanocomposites measured by dynamic mechanical thermal analysis were increased compared with untreated nanosilica‐treated PVC composite. A much more efficient transfer of stresses was permitted from the polymer matrix to the hybrid silica nanoparticles. The filling of the hybrid nanoparticles caused the improved mechanical properties (tensile strength, notched impact strength, and rigidity) when the filler content was not more than 3 wt %. Permeability rates of O₂ and H₂O through films of PMMA‐grafted‐SiO₂/PVC were also measured. Lower rates were observed when compared with that of neat PVC. This was attributed to the more tortuous path which must be covered by the gas molecules, since SiO₂ nanoparticles are considered impenetrable by gas molecules. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Tensile and Impact Properties of Hollow Glass Bead‐Filled PVC Composites

The tensile and notched Izod impact properties of poly(vinyl chloride) (PVC) composites filled with hollow glass beads (HGB) were measured at room temperature by means of an Instron materials testing machine to investigate the effects of the filler content and size on these mechanical properties. The results showed that the tensile yield strength (σ_yc) decreased gently with increasing HGB volume fraction (ϕ _f), while the tensile break strength (σ_bc) of the composites was somewhat greater than that of the unfilled PVC within ϕ _f = 0–20%. In addition, the dependence of σ_bc on ϕ _f was not obvious. The effect of HGB size on both σ_yc and σ_bc was insignificant. When ϕ _f < 5%, the notched impact strength (σ_IC) of the composites decreased quickly with increasing ϕ _f, and then it decreased slightly with the increase of ϕ _f. Similarly, the influence of the filler size on the impact properties was insignificant. Furthermore, the σ_yc of the samples was estimated using a tensile equation proposed in a previous paper. A good agreement was shown between the calculations and the measured data.     

A rheological study of the ageing of emulsion and microsuspension-based PVC plastisols

A PVC plastisol is a homogeneous dispersion of PVC resin in a liquid continuous phase consisting basically of a plasticizer and a thermal stabilizer; the PVC resin being usually a fine powder is polymerized by emulsion or microsuspension processes. Plastisol rheology is affected by many aspects of the plastisol formulations, such as type and amount of each ingredient, the mixing procedure, temperature, and the effect of PVC resin properties. In this work, the ageing behavior of PVC plastisols with different resin types was studied, with the results showing an unexpected behavior in the elastic modulus, probably originating from plasticizer adsorption at the surface of the PVC particles. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Thermal and mechanical properties of linear low‐density polyethylene/low‐density polyethylene/wax ternary blends

The thermal and mechanical properties of uncrosslinked three‐component blends of linear low‐density polyethylene (LLDPE), low‐density polyethylene (LDPE), and a hard, paraffinic Fischer–Tropsch wax were investigated. A decrease in the total crystallinity with an increase in both LDPE and wax contents was observed. It was also observed that experimental enthalpy values of LLDPE in the blends were generally higher than the theoretically expected values, whereas in the case of LDPE the theoretically expected values were higher than the experimental values. In the presence of higher wax content there was a good correlation between experimental and theoretically expected enthalpy values. The DSC results showed changes in peak temperature of melting, as well as peak width, with changing blend composition. Most of these changes are explained in terms of the preferred cocrystallization of wax with LLDPE. Young's modulus, yield stress, and stress at break decreased with increasing LDPE content, whereas elongation at yield increased. This is in line with the decreasing crystallinity and increasing amorphous content expected with increasing LDPE content. Deviations from this behavior for samples containing 10% wax and relatively low LDPE contents are explained in terms of lower tie chain fractions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1748–1755, 2005     

NBR/PVC橡塑共混发泡材料的影响因素研究

通过调整橡塑并用配比、硫化体系、发泡剂用量、增塑剂邻苯二甲酸二辛酯(DOP)用量以及填料碳酸钙的用量研究其对共混发泡材料的影响。结果表明:当丁腈橡胶(NBR)/聚氯乙烯(PVC)并用配比为70/30时,发泡制品闭孔率最高,密度最小,力学性能最好;发泡制品密度随硫磺用量的增加呈现增加趋势,在低硫高促体系下,硫化速度和发泡速度匹配最好,制品性能最佳;在合适的硫化体系下,发泡制品密度随发泡剂量的增加而减小;随增塑剂DOP用量的增加,制品密度逐渐减小,当DOP用量为30份时,得到制品闭孔率最高;碳酸钙用量对模压发泡制品影响明显,其用量越多,密度越高。     

Dynamic mechanical properties of polystyrene‐co‐styrenesulfonic acid copolymers neutralized with aliphatic diamines

In this article, we reported the effects of the addition of various aliphatic diamines (ADAs) on the dynamic mechanical properties of poly(styrene‐co‐styrenesulfonic acid) copolymers. It was found that the ionic modulus decreased with increasing chain length of ADAs but increased for the ADA12‐containing ionomers. Upon the neutralization of the copolymers with ADAs, a minor change in the size and position of the matrix loss tangent peak was observed. However, the position of the cluster loss tangent peaks shifted to lower temperatures, and the shift rate depended on the chain length of ADAs. Thus, it was suggested that the ADAs acted mainly as preferential plasticizer for the cluster regions. In addition, the effect of the amount of ADA on the difference between the matrix and cluster temperatures of the ionomers was strongest than that of the type of ADA or ion content. The X‐ray peak of ADA12 suggested that the ADA12 acted both as plasticizer and as filler. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of melt‐processable polyimides derived from 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene

A series of molecular‐weight‐controlled imide resins end‐capped with phenylethynyl groups were prepared through the polycondensation of a mixture of 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene and 1,3‐bis(4‐aminophenoxy)benzene with 4,4′‐oxydiphthalic anhydride in the presence of 4‐phenylethynylphthalic anhydride as an end‐capping agent. The effects of the resin chemical structures and molecular weights on their melt processability and thermal properties were systematically investigated. The experimental results demonstrated that the molecular‐weight‐controlled imide resins exhibited not only meltability and melt stability but also low melt viscosity and high fluidability at temperatures lower than 280°C. The molecular‐weight‐controlled imide resins could be thermally cured at 371°C to yield thermoset polyimides by polymer chain extension and crosslinking. The neat thermoset polyimides showed excellent thermal stability, with an initial thermal decomposition temperature of more than 500°C and high glass‐transition temperatures greater than 290°C, and good mechanical properties, with flexural strengths in the range of 140.1–163.6 MPa, flexural moduli of 3.0–3.6 GPa, tensile strengths of 60.7–93.8 MPa, and elongations at break as high as 14.7%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

PVC基热塑性弹性体的制备

采用机械共混法制备PVC基弹性体，研究了聚合物的质量配比、增塑剂的用量及增塑剂的配合使用对体系性能的影响，并考察了填料对体系性能的影响。结果表明，通过不同的聚合物质量配比、增塑剂的选择以及不同填料的选用，可制得不同性能的热塑性弹性体。     

Influence of matrix viscosity on the dynamic mechanical performance of magnetorheological elastomers

Anisotropic magnetorheological elastomers (MREs) with different natural rubber matrix viscosities and industrial waste nickel zinc ferrite were prepared in order to assess the dynamic and mechanical performance of the materials. The curing characteristics of the anisotropic MREs were determined using a moving disk rheometer (MDR 2000). The loss tangent (tan δ) was measured through a parallel-plate rheometer over a frequency range of 1─100 Hz (Hz) and a strain amplitude range of 0.1─6%. It was found that tan δ increased with increasing matrix viscosity over the range of frequency and strain amplitude explored. Furthermore, as the matrix viscosity increased, the height of the tan δ peak also increased and the glass transition temperature (T_g) valued shifted to a higher temperature. It was also found that tensile strength and elongation at break increased with increasing matrix viscosity. The SEM micrographs revealed that the columnar structures became longer and thicker with a decrease in matrix viscosity. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48492.