Epoxidized castor oil-based diglycidyl-phthalate plasticizer: Synthesis and thermal stabilizing effects on poly(vinyl chloride)

Epoxidized castor oil-based diglycidyl-phthalate (ECODP) was synthesized and incorporated into poly(vinyl chloride) (PVC) for the first time. The chemical structure of the ECODP was confirmed. The plasticizing effects of ECODP as a replacement for commercial plasticizer dioctyl phthalate (DOP) were investigated. The thermal stability and mechanical properties of PVC films before and after aging were investigated using thermogravimetric analysis (TGA), TGA-FTIR analysis, dynamic mechanical analysis (DMA), and tensile tests. The results indicated that PVC films plasticized with ECODP significantly improved thermal stability, compatibility, and flexibility. When DOP was substituted with ECODP completely, the initial decomposition temperature, 5, 10, 50, and 70% mass loss temperatures (T_i, T₅, T₁₀, T₅₀, and T₇₀) increased by 24.7, 38.9, 32.0, 30.3, and 102.7 °C, respectively. The functional mechanism of the ECODP as a thermal stabilizing plasticizer and the plasticization mechanism of PVC composites were also investigated. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47142.     

Synthesis of a bio-based plasticizer from vanillic acid and its effects on poly(vinyl chloride)

A new bio-based plasticizer, VA8-8, was prepared derived from vanillic acid, and its structure was verified by nuclear magnetic resonance. It was incorporated into poly(vinyl chloride) (PVC) to replace dioctyl phthalate (DOP), and its plasticizing performance was evaluated. The results indicated that VA8-8 shows good compatible with PVC resin, and has a excellent plasticizing effect for PVC. When DOP was partially or completely substituted with VA8-8, the T_g value PVC blends dropped from 34.6 to 24.3°C and the elongation at break increased from 196.4% to 301.9%, suggesting the enhanced plasticizing efficiency of plasticizer. The plasticizing mechanism was also simulated, and the interactions between VA8-8 and PVC molecules were discussed. The thermogravimetric analysis showed VA8-8 can more effectively improve the thermal stability of PVC than DOP. In addition, the migration resistance of VA8-8 was generally superior to that of DOP. Therefore, VA8-8 is a comparable to or better plasticizer than DOP, and it is a promising alternative plasticizer for PVC.     

Sustainable synthesis of bio‐based hyperbranched ester and its application for preparing soft polyvinyl chloride materials

In this study, bio‐based hyperbranched ester was synthesized from castor oil. The chemical structure of the bio‐based hyperbranched ester obtained was characterized with Fourier transform infrared and ¹H NMR spectra. Soft polyvinyl chloride (PVC) materials were prepared via thermoplastic blending at 160 °C using bio‐based hyperbranched ester as plasticizer. The performances including the thermal stability, glass transition temperature (T_g), crystallinity, tensile properties, solvent extraction resistance and volatility resistance of soft PVC materials incorporating bio‐based hyperbranched ester were investigated and compared with the traditional plasticizer dioctyl phthalate (DOP). The results showed that bio‐based hyperbranched ester enhanced the thermal stability of the PVC materials. The T_g of PVC incorporating bio‐based hyperbranched ester was 23 °C, lower than that of PVC/DOP materials at 28 °C. Bio‐based hyperbranched ester showed a better plasticizing effect, solvent extraction resistance and volatility resistance than DOP. The plasticizing mechanism is also discussed. © 2018 Society of Chemical Industry     

Characterization of PVC cable insulation materials and products obtained after removal of additives

Organic solvents cyclohexane, dichloromethane, hexane, and tetrahydrofuran were tested to separate the dioctylphthalate (DOP) as plasticizer from the poly(vinyl chloride) (PVC)‐based materials. It was found that the efficiency of ultrasound‐enhanced hexane extraction of the DOP from PVC is 70% and the efficiency of the separation of the DOP and other compounds from the PVC by dissolution in THF followed by subsequent precipitation was 98–99%. Differential scanning calorimetry (DSC) and thermogravimetry (TG) were used to characterize the thermal behavior of PVC materials before and after extraction of plasticizers. It was found that during heating in the range 20–800°C the total mass loss measured for the nontreated, extracted, and precipitated PVC samples was 71.6, 66.6, and 97%, respectively. In the temperature range 200–340°C, the release of DOP, HCl, and CO₂ was observed by simultaneous thermogravimetry (TG)/FTIR. The effect of plasticizers on thermal behavior of PVC‐based insulation material was characterized by DSC in the range ?40–140°C. It was found that, concerning the PVC cable insulation material before treatment, the value of the glass transition temperature (T_g) was 1.4°C, whereas for the PVC sample extracted by hexane, the value of T_g was 39.5°C and for the PVC dissolved in THF and subsequently precipitated, the value of T_g was 80.4°C. Moreover, the PVC samples after extraction of plasticizers, fillers, and other agents were tested to characterize their thermal degradation. The TG and FTIR results of chemically nontreated, extracted, and precipitated samples were compared. The release of DOP, HCl, CO₂, and benzene was studied during thermal degradation of the samples by FTIR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 788–795, 2006     

Synthesis and evaluation of dialkyl furan-2,5-dicarboxylates as plasticizers for PVC

Di(2-ethylhexyl), di(2-octyl), dihexyl, and dibutyl furan-2,5-dicarboxylate were synthesized from furfural and characterized for their plasticizing abilities toward PVC by dynamic mechanical thermal analysis (DMTA) with di(2-ethylhexyl) phthalate (DOP) as the standard of reference. DMTA gave values for the depression of the glass transition temperature (T_g) per mass fraction of plasticizer, and it also yielded a set of parameters, relative to those for DOP, which describe the compatibility of the furan diesters with PVC. The efficiency in lowering T_g as exhibited by di(2-ethylhexyl) furan-2,5-dicarboxylate is similar to that of its benzenoid analog, DOP, and was determined at 2.41 and 2.45°C per mass % plasticizer, respectively. All four furan diesters were found to be more compatible toward PVC than toward DOP, with dibutyl furan-2,5-dicarboxylate the most highly compatible. © 1994 John Wiley & Sons, Inc.     

Effect of ketal group in castor oil acid-based plasticizer on the properties of poly(vinyl chloride)

Two castor oil acid esters containing a ketal or ketone group (KCL or CL), as alternative plasticizers for poly(vinyl chloride) (PVC), were prepared. The structures were confirmed by ¹H NMR and FTIR spectroscopies. The effects of the presence of a ketal or ketone group in these compounds on PVC plasticization were examined. The DMA and SEM results showed that both plasticizers were miscible with PVC and exhibited excellent plasticizing properties, compared to those of dioctyl phthalate (DOP). The PVC plasticized by KCL displayed a lower T_g value of 20.6 ° C, which was lower than that of PVC plasticized with DOP (22.3 ° C) and PVC plasticized with CL (40.5 ° C). Tensile tests indicated that PVC plasticized using KCL showed a 37% higher of elongation at break than PVC plasticized by CL and 30% higher than PVC plasticized by DOP. The plasticizing mechanism was also investigated. Moreover, exudation, volatility, and extraction tests, along with TGA indicated that the presence of ketal groups effectively improved the migration resistance of plasticizer and the thermal stability of PVC blends. Taken together, introducing ketal groups into plasticizer might be an effective strategy for improving its plasticizing efficiency.     

Polyhedral oligomeric silsesquioxane as a novel plasticizer for poly(vinyl chloride)

This study focuses on investigating the use of polyhedral oligomeric silsesquioxanes (POSS) to plasticize poly(vinyl chloride) (PVC). Conventional organic plasticizers for PVC, such as dioctyl phthalate (DOP), are somewhat volatile, leading to plasticizer loss and unwanted deterioration of the material properties over time. Previous experimental results indicate that methacryl-POSS, which is much less volatile due to its hybrid organic-inorganic structure, has the ability to plasticize PVC. Methacryl-POSS is miscible in the PVC only up to 15 wt%, thereby limiting its suitability as a plasticizer. However, through the use of ternary compositions it is possible to increase the proportion of methacryl-POSS in PVC substantially. The T_g of appropriately formulated ternary PVC/POSS/DOP compounds can be reduced to near room temperature, and these materials exhibit desirable ductile behavior. Binary (PVC/DOP) and ternary (PVC/POSS/DOP) compounds formulated to the same T_g values showed considerably different mechanical properties. Such findings reveal the possibility of using POSS to engineer the mechanical properties of plasticized PVC.     

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     

Dielectric and mechanical properties of poly(vinyl chloride)–dioctylphthalate systems

The mechanical properties, tensile strength, and elongation were investigated for poly(vinyl chloride) (PVC) samples mixed with dioctylphthalate (DOP) at concentrations from 0 to 100 parts per hundred parts PVC at 23°C. It was found that the tensile strength decreased with the increase of concentration, and the elongation was increased until a concentration of 30 DOP content, and then decreased. This leads to the suggestion that intermolecular plasticization is dominant until 30 DOP content, while interstructural plasticization is prevailing for higher concentrations. The permittivity ε′ and the dielectric loss factor ε″ of the same samples have been measured in the frequency range 10²–10⁵ Hz at temperatures from 3 to 96°C. Results show that as the DOP content increases in PVC, the dielectric absorption becomes broader, and the glass transition temperature T_g is lowered. The magnitude of the loss peak decreases with an increase of DOP content to a minimum at concentrations from 40 to 60 DOP content. At higher concentrations the loss peak is increased and T_g is unaltered. Another absorption was observed at 100 Hz and at high temperatures, which was attributed to Maxwell–Wagner effect or direct current conductivity or both of them. It was found that the sample containing 40 parts DOP in 100 parts PVC possesses the best mechanical and electrical properties.     

Dynamic rheological behavior and microcrystalline structure of dioctyl phthalate plasticized poly(vinyl chloride)

The dynamic rheological behavior of poly(vinyl chloride) (PVC)/dioctyl phthalate (DOP) systems were studied as a function of DOP content and melting temperature. The dynamic rheological behavior of the PVC/DOP systems was found to be remarkably affected by the DOP content. The observed curves of storage modulus (G′) versus frequency were well fitted to an empirical equation (G′ = G′₀ + Kωⁿ, where G′₀ is the low‐frequency yield value of the storage modulus, the exponent n is a dependent index of frequency, K is a constant coefficient, and ω is the angular frequency). The loss tangent and/or phase angle increased remarkably at a higher DOP content. There was an apparent critical DOP content transition where the dynamic rheological behavior of the PVC/DOP systems changed greatly. Scanning electron microscopy observations revealed the existence of a multiscale particle structure in the PVC/DOP systems. For the PVC/DOP (100/70) system, with increasing melting temperature, its dynamic rheological behavior showed an apparent mutation at about 190°C. Differential scanning calorimetry (DSC) analysis confirmed that the high elastic networks in the PVC/DOP systems were closely related to the microcrystalline structure of PVC. The transitions in the curves of the gelation degree and crystallinity versus the DOP content corresponded well to the DOP content transition in the dynamic rheological behavior. DOP could inhibit the secondary crystallite of PVC and almost had no effect on the primary crystallite of PVC. The coexistence of the microcrystalline structure of PVC and the plasticizer (DOP) resulted in high elastic networks in the PVC/DOP systems. The DSC results explained the DOP content transition and the temperature transition in the dynamic rheological behavior of the PVC/DOP systems well. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Fusion behavior of plastisols of PVC studied by ATR-FTIR

The behavior of PVC plastisols during gelation and fusion was studied by the ATR-FTIR technique (Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy). DBP, DOP, and DIDP, three common phthalate plasticizers for PVC, were used in plastisols formulations. Three heating rates—5, 10 and 15°C/min—and formulations with different plasticizer concentrations were studied. The IR spectra of a plastisol coincides with the IR spectra of the plasticizer except for the bands at 1435 and 613 cm^?1 from the PVC (CH₂ wagging and C—Cl stretching, respectively). When the plastisol is heated, a progressive decrease of the plasticizer bands areas can be observed, while bands from PVC increase their intensity, probably because of the adsorption of the plasticizer by the resin. On cooling, the area of all bands follows the same path as when heating, but the paths separate at a certain temperature, showing the irreversible nature of this process. The analysis of the band at 1280 cm^?1 (C(O)—O from plasticizer) during heating and cooling, shows that the temperature of separation areas (T_s) takes place at temperatures coherent with plasticizer compatibility. Studies at different heating rates and different plasticizer content are in good agreement with results using other techniques, available in the literature.     

Poly(vinyl chloride) plasticized with succinate esters: synthesis and characterization

Phthalates pose adverse health effects due to their propensity to leach and the most common, di(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DOP), are petroleum-based. Conversely, di-esters, succinates are biobased (produced from fermentation of biomass), biodegradable, and therefore potential sustainable replacements for phthalates. A series of succinates, di-octyl succinate (DOS), di-hexyl succinate (DHS), di-butyl succinate (DBS), and di-ethyl succinate (DES), were mixed with poly(vinyl chloride) (PVC). The interaction of the plasticizer ester carbonyl with PVC shows an average −5 cm⁻¹ shift of the carbonyl absorbance peak energy. The glass transition temperatures (T _g), were monitored by differential scanning calorimetry and dynamic mechanical analyses. The T _gs of DOS and DHS plasticized PVC were significantly lower than DOP plasticized PVC at a lower percent mass. On the other hand, PVC plasticized with either DBS or DES exhibited a similar trend in lowering the T _g as that of DOP plasticized PVC.     

Polyblends. I. Mechanical properties of polyblends of butadiene–acrylonitrile elastomers and copolymers of vinyl stearate and vinyl chloride

Several nitrile rubber elastomers were polyblended, across the composition range, with selected polymeric compositions containing vinyl chloride. The compositions incorporated were (a) bulk poly(vinyl chloride) (PVC); (b) copolymers of vinyl stearate and vinyl chloride containing, respectively, 0.21, 0.36, and 0.47 weight fraction of the vinyl ester; and (c) mixtures containing the same weight fractions of di-2-ethylhexyl phthalate (DOP) with PVC. Mechanical, viscoelastic, optical, and volatility properties were studied on all blends in this first paper. To accurately compare the mechanical properties of polyblends of different systems, a criterion of mechanical equivalence was taken as the observance of similar stresses at break for compositions selected to have identical 100% moduli. Optimum mechanical equivalence, therefore, occurred at the largest ratios of 100% modulus to break stress for all systems compared. Optimum mechanical property equivalence was observed for NBR blends with PVC and for similar blends of both internally and externally plasticized systems containing 0.21 weight fraction of plasticizer. However, considerably more nitrile rubber was needed for PVC blends to acquire the properties of the plasticized systems. Mechanical equivalence was observed, but was not optimum for systems having more plasticizer because tensile strengths were lower. Polyblending with NBR improved the toughness and low-temperature properties of starting vinyl stearate copolymers. Improved toughness was indicated by the expansion of areas under stress–strain curves. Refractive index matching appeared to explain the transparency of the best films and their relative freedom from haze. On heating at 85°C, poly(vinyl chloride) and the copolymer polyblends suffered no volatility loss. Volatility of DOP from the blends was 1.5 times greater than for PVC–DOP mixtures. Because modulus–temperature curves and mechanical T_g values of the filler component shifted with composition, the mechanical behavior of these blends was in harmony with an accepted standard of interdomain compatibility.     

Plasticizer diffusion into PVC particles as studied by ESR spin probe method

Summary The spin probe technique of electron spin resonance (ESR) spectroscopy has been applied for studying the plasticizer diffusion, migration, and redistribution processes in suspension polymerized PVC particles. In the first series of experiments six PVC powder samples with different K values (58, 61, 64, 67, 70, and 72) were mixed with diisooctyl phthalate (DOP) containing 10^–4 M 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) as stable free radical spin probe. In the second run TEMPO-doped dry PVC powders were mixed with DOP plasticizer. Finally we studied the plasticizer transport phenomena between plasticized and non-plasticized polymer particles in powder mixtures. The observed diffusion properties of different samples were interpreted in terms of the different porosities of powders.     

Plasticizer diffusion as the rate-determining step in dry blending of poly(vinyl chloride)

Differential thermal analysis has been used to examine the process of dry blending of plasticizer and PVC. The rate of transformation of the glass transition from that of the polymer initially in the cold mix to the glass transition of the blend (blend T_g) has been examined at various temperatures from room temperature to above the polymer T_g. The dependence on temperature of this rate of transformation of the observed T_g is similar to the temperature dependence of the diffusion of plasticizer into PVC. It is concluded that diffusion of plasticizer into polymer particles is the rate-determining step in the dry blending of PVC. It also appears that a single mechanism of diffusion is involved both below and above the glass transition of the polymer.     

Migration of Epoxidized Sunflower Oil and Dioctyl Phthalate from Rigid and Plasticized Poly(vinyl chloride)

The aim of this paper is the determination of the specific migration of epoxidized sunflower oil (ESO) from rigid and plasticized poly(vinyl chloride) (PVC) into food simulants. ESO was obtained by epoxidation of commercial sunflower oil and used as a thermal organic co-stabilizer for PVC. For that purpose, rigid and plasticized (0, 15, 30, and 45 wt% of dioctyl phthalate or DOP) PVC films stabilized with ESO in the presence of Zn and Ca stearates were used to perform migration testing in olive oil. The test conditions were 12 d at 20 and 40°C and 2 h at 70°C with and without agitation.

The determination of ESO migration was carried out by gas chromatography-mass spectrometry (GC-MS). ESO was quantified by an external standard addition method, using linoleic acid (C_18:2) as the external standard. The influence of various parameters, such as the agitation and time of contact, the temperature, the presence or the absence of the plasticizer, and the plasticizer concentration, was considered.     

Effects of hydrothermal ageing on the thermal behaviour of poly(vinyl chloride) filled with wood flour

The hydrothermal ageing of wood‐flour‐filled PVC produced by dry‐blending in a high‐speed mixer in the presence of a plasticizer and other processing additives was carried out to investigate its thermal behaviour, and the results obtained were compared with those for the unfilled material. The dry‐blended compounds were prepared as films by a calendering process. The accelerated hydrothermal ageing was carried out by immersing the samples in boiling water at 100 °C for 110 h. The thermal behaviour of the reference and the aged samples in water was characterized by differential scanning calorimetry (DSC) and determination of the weight changes. The study has shown that during hydrothermal ageing, the samples from the whole formulations absorbed water, for instance, for 30 wt% filled PVC (F30), 16 wt% of water absorption was obtained, while this was only 2.2 wt% for unfilled PVC (F0). It was also noticed that the formulations filled with wood flour up to 10 wt% exhibited similar water absorption kinetics, i.e. the water was mostly absorbed during the first 50 h and the amount absorbed was less than 5 wt%. On the other hand, the 30 wt% filled samples regularly absorbed water up to almost 16 wt% after 100 h of immersion. The DSC data showed that hydrothermal ageing significantly affected the onset temperature of decomposition (T_d) of the unfilled samples by decreasing this temperature from 228 to 215 °C. For the 30 wt% filled samples, only additive migration was observed, while the T_d remained almost unchanged. Furthermore, from the DSC data, processability of the 30 wt% filled PVC samples at elevated temperatures, i.e. 180 to 200 °C was shown. Copyright © 2004 Society of Chemical Industry     

Mechanical and morphological properties for sandwich composites of wood/PVC and glass fiber/PVC layers

This work manufactured sandwich composites from glass fiber/poly(vinyl chloride) (GF/PVC) and wood/PVC layers, and their mechanical and morphological properties of the composites in three GF orientation angles were assessed. The effects of K value (or viscosity index) of PVC and Dioctyl phthalate (DOP) loading were of our interests. The GF/PVC was used as core layer whereas wood/PVC was the cover layers. The experimental results indicated that PVC with low K value was recommended for the GF/PVC core layer for fabrication of GF/WPVC sandwich composites. The improvement of PVC diffusion at the interface between the GF and the PVC core layer was obtained when using PVC with K value of 58. This was because it could prevent de‐lamination between composite layers which would lead to higher mechanical properties of the sandwich composites, except for the tensile modulus. The sandwich composites with 0° GF orientation possessed relatively much higher mechanical properties as compared with those with 45° and 90° GF orientations, especially for the impact strength. Low mechanical properties of the sandwich composites with 45° and 90° GF orientation angles could be overcome by incorporation of DOP plasticizer into the GF/PVC core layer with the recommended DOP loadings of 5–10 parts per hundred by weight of PVC components. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Rosin‐derived poly(vinyl chloride) plasticizer: Synthesis,structure, and properties

In this work, rosin‐based plasticizer was synthesized by Diels–Alder (DA) and esterification. First, the maleopimaric acid (RT) was obtained by DA between the double bond of rosin and maleic anhydride. Then, the carboxyl group and anhydride group of RT was esterified with tetrahydro geraniol to obtain the rosin‐based polyacid esters (RTT) under the catalysis of p‐toluene sulfonic acid. The structure of RT and RTT was detected by FTIR and ¹H‐NMR. RTT was used as main plasticizer to obtain plasticized polyvinyl chloride (PVC) materials and compared with DOP. The results showed that RTT improved the thermal stability and reduced T_g of PVC film. Plasticized PVC films had excellent mechanical properties with the elastic modulus of ?4,793.67 MPa and tensile strength of ?111.86 MPa, higher than that of pure PVC and DOP‐6. RTT showed better volatility stability, migration, and solvent extraction in PVC compared to DOP. J. VINYL ADDIT. TECHNOL., 26:180–186, 2020. © 2019 Society of Plastics Engineers     

Synthesis of difuran diesters from furfural,and their evaluation as plasticizers for polyvinyl chloride

The compounds 1,1-bis[5-(2-ethylhexyl, 2-octyl, hexyl, and butyl)carboxylate-2-furyl)ethane, and 5,5′-dihexylcarboxylate-2,2′ bifuran were synthesized from furfural and characterized for their plasticizing abilities toward polyvinyl chloride (PVC) by dynamic mechanical thermal analyses (DMTA) with di-(2-ethylhexyl)phthalate (DOP)as the standard of reference. DMTA gave values for the depression of the glass-transition temperature (T_g) per mass fraction of plasticizer, and it also yielded a set of parameters, relative to those of DOP, which describe the compatability of the furan diesters with PVC. These values are compared to those of DOP and furan diesters incorporating only one furan ring in the molecular structure, which have previously been tested by this method. The difuran plasticizers are less efficient in lowering T_g than the monofuran plasticizers or DOP, with 1,1-bis[5-(2-octyl)carboxylate-2-furyl]ethane the least efficient and 1,1-bis(5-hexylcarboxylate-2-furyl)ethane the most efficient. On average the compatability toward PVC is better than that of DOP, and similar to that of analogous monofuran structures. © 1995 John Wiley & Sons, Inc.