Formulation and properties' evaluation of PVC/(dioctyl phthalate)/(epoxidized rubber seed oil) plastigels

Epoxidized rubber seed oil (4.5% oxirane content, ERSO) was prepared by treating the oil with peracetic acid generated in situ by reacting glacial acetic acid with hydrogen peroxide. The thermal behavior of the ERSO was determined by differential scanning calorimetry. The effect of the epoxidized oil on the thermal stability of poly (vinyl chloride) (PVC) plastigels, formulated to contain dioctyl phthalate (DOP) plasticizer and various amounts of the epoxidized oil, was evaluated by using discoloration indices of the polymer samples degraded at 160°C for 30 min and thermogravimetry at a constant heating rate of 10°C/min up to 600°C. The thermal behavior of the ERSO was characterized by endothermic peaks at about 150°C, which were attributed to the formation of network structures via epoxide groups, and at temperatures above 300°C, which were due to the decomposition of the material. Up to 50% of the DOP plasticizer in the PVC plastisol formulation could be substituted by ERSO without a marked deleterious effect on the consistency of the plastigel formed. In the presence of the epoxidized oil, PVC plastigel samples showed a marked reduction in discoloration and the number of conjugated double bonds, as well as high temperatures for the attainment of specific extents of degradation. These results showed that the ERSO retarded/inhibited thermal dehydrochlorination and the formation of long (n > 6) polyene sequences in PVC plastigels. The plasticizer efficiency/permanence of ERSO in PVC/DOP plastigels was evaluated from mechanical properties' measurements, leaching/migration tests, and water vapor permeability studies. The results showed that a large proportion of DOP could be substituted by ERSO in a PVC plastisol formulation without deleterious effects on the properties of the plastigels. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.     

环保型钙锌复合热稳定剂与增塑剂在 PVC中的协效作用研究

将生物基增塑剂橡胶籽油基环氧脂肪酸甲酯（ERSO）与热稳定剂油脂源多聚脂肪酸基钙锌（OMFCTS）复配,以β-二酮作辅助热稳定剂,改性聚氯乙烯（PVC）,通过热老化烘箱法、刚果红法、热重分析（TGA）、热重红外联用（TGA-FTIR）分析、热重质谱联用（TGA-MS）分析、力学性能测试及动态力学性能分析（DMA）考察了改性PVC的热稳定性及力学性能,并对8个配方改性后PVC的性能进行了对比。结果表明：与DOP/CaSt₂/ZnSt₂、DOP/OMFCTS和ERSO/CaSt₂/ZnSt₂体系相比,ERSO/OMFCTS体系的热稳定性最优,力学性能较好,改性PVC的玻璃化转变温度（38.2℃）最低,拉伸断裂伸长率达265.6%;静态热稳定时间（200℃）最长（46'21"）。ERSO和OMFCTS具有良好的协同作用,二者可有效替代传统增塑剂邻苯二甲酸二辛酯（DOP）及热稳定剂硬脂酸钙锌（CaSt₂/ZnSt₂）。     

Thermal dehydrochlorination of PVC in the presence of rubber seed oil

Dehydrochlorination rates of PVC in nitrogen atmosphere were determined in the presence of rubber seed oil (RSO), epoxidized rubber seed oil (ERSO), barium soap of rubber seed oil fatty acids and barium soap of epoxidized fatty acid of rubber seed oil. The initial rates of dehydrochlorination and the time required for the degradation to attain 1% conversion showed that the rubber seed oil derivatives exert a stabilizing effect on the degradation of PVC. The order of the stabilizing effect was found to be metal soaps of ERSO < metal soaps of RSO < ERSO < RSO.     

The Reaction of Plumbonacrite (Basic Lead Carbonate) with Hot DOP,and the Stabilisation of Plasticised PVC

The basic lead carbonate ‘plumbonacrite’, 6PbCO₃.3Pb(OH)₂.PbO, has been reacted with di-2-ethyl hexyl phthalate (dioctyl phthalate, DOP), C₆H₄(COOC₈H₁₇)₂ at 180d?C under nitrogen. Anhydrous monobasic lead orthophthalate, PbO.Pb₆H₄(COO)₂, was the only product detected by X-ray powder diffraction (X.R.P.D.). These studies are related to previous work on reactions taking place in hot polyvinyl chloride (PVC) blends containing DOP plasticiser and basic lead stabilisers. It is concluded that plasticiser stabiliser interaction can play a significant role in stabilising PVC against thermal decomposition, and that efficient stabilisation takes place largely by a free-radical exchange mechanism. Characteristic X.R.P.D. data are tabulated for anhydrous monobasic lead orthophthalate, and for monobasic lead orthophthalate monohydrate, PbO. PbC₆H₄(COO)₂- H₂O, which can be made in aqueous suspension and which converts to the anhydrous salt at 180d?C. X.R.P.D. data are also given for dibasic lead orthophthalate, 2PbO.PbC₆H₄(COO)₂.1/2H₂O, which is well known as a stabiliser for PVC, and which might have been expected to form in these experiments, (but did not in fact do so).     

Bacterial degradation of plasticised PVC-effect on some physical properties

Burial tests on plasticised PVC in neutral soil inoculated with species of Pseudomonas and Brevibacterium have shown degradation in 8 weeks that is largely dependent on the nature of the plasticiser. There was no evidence for any attack on the polymer itself. Phthalate and phosphate plasticisers were resistant; adipate, azelate and sebacate plasticisers were susceptible and a number of others, e.g. chlorinated hydrocarbon and epoxy types, occupied an intermediate position. The degree of attack was also dependent on the nature of the stabiliser used in the PVC formulation, lead-based stabiliser conferring less resistance than barium/cadmium-based stabiliser. Degradation has been assessed in terms of loss in weight, change of stiffness and loss of energy during cyclic deformation.     

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.     

Synthesis and application of an environmental epoxy plasticizer with phthalate-like structure based on tung oil and cardanol for poly(vinyl chloride)

An epoxidized cardanol tungoleate (ECT) based on tung oil and cardanol was synthesized through esterification and epoxidation. The chemical structure of the compound was verified by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H-NMR). The plasticizing effects of ECT as the main plasticizer in poly(vinyl chloride) (PVC) was studied and compared with the commercial plasticizer dioctyl phthalate (DOP). The thermal migration stabilities, the thermal degradation process and the mechanical properties of PVC samples and the plasticization mechanism of ECT for PVC were investigated through the use of volatility, extraction, discoloration, and tensile tests as well as thermal gravity analysis (TGA), TGA–FTIR analysis, electronic universal testing machine and dynamic mechanical analysis (DMA). Compared with DOP, the ECT plasticized PVC can exhibits better thermal stability, more excellent tensile strength (17.28 MPa) and higher stretchability (629.41%), which is 1161% higher than DOP (1.37 MPa) plasticized PVC film. In addition, the migration resistance and volatility stability of ECT are much better than DOP. Therefore, this fully bio-based plasticizer based on tung oil and cardanol is a promising alternative plasticizer for PVC and may be an excellent phthalate substitute from the perspective of human health and sustainable development.     

Studies on epoxidized rubber seed oil as plasticizer for acrylonitrile butadiene rubber

The application of rubber seed oil (RSO) and epoxidized RSO (ERSO) as a plasticizer in acrylonitrile butadiene rubber (NBR) was studied using RSO and ERSO with different levels of epoxidation. The results indicated that ERSO could be used as a less leachable and low volatility plasticizer for NBR. The use of ERSO in NBR gave better abrasion resistance whereas the tensile strength and tear strength were comparable to those vulcanizates that contained dioctyl phthalate as a plasticizer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 668–673, 2003     

Effects of poly(1,2‐propylene glycol adipate) and nano‐CaCO3 on DOP migration and mechanical properties of flexible PVC

Nano‐CaCO₃ was used as nano‐scale filler and poly(1,2‐propylene glycol adipate) (PPA) was used as polymeric plasticizer in flexible poly(vinyl chloride) (PVC) sheets for the partial replacement of di(2‐ethyl hexyl) phthalate (DOP) in this paper. The effect of PPA and nano‐CaCO₃ on restraining DOP migration was evaluated via extraction tests. The results showed that the introduction of nano‐CaCO₃ can decrease the extraction rate of DOP in the PVC matrix. The tensile strength and elongation at break of CaCO₃‐1/PPA‐20/DOP‐30/PVC were similar to those of DOP‐50/PVC, and CaCO₃‐1/PPA‐20/DOP‐30/PVC exhibited the superior suppression of DOP migration compared with DOP‐50/PVC. Thermogravimetry analysis (TGA) indicated that the addition of nano‐CaCO₃ effectively improved the thermal stability of the nanocomposites. Therefore, the combination of PPA and nano‐CaCO₃ is an effective approach to suppress the migration of DOP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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     

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.     

Recycling of Waste PET: Usage as Secondary Plasticizer for PVC

Postconsumer water bottle poly(ethylene terephthalate) (PET) flakes were depolymerized with ethylene glycol (EG) by the glycolysis reaction in the presence of zinc acetate as the catalyst. In the depolymerization reactions, different weight ratios of PET/EG were used. In order to obtain polyesters used as PVC plasticizers, these glycolysis products containing hydroxyl end groups were reacted with an adipic acid (AA)–containing diacid group at equivalent amounts. In order to obtain PVC plastisols, PVC was dispersed into a plasticizers' mixture composed of di-isooctyl phthalate (DOP) and polyester products by using a high-speed mixer (PVC/plasticizers, 65/35 w/w). For the preparation of plasticizer mixture polyester products were used at a weight ratio of 20%, 40%, 60% of DOP. Plasticized PVC sheets were prepared from plastisols and their glass transition temperatures (T_g), migration, and mechanical properties were determined. The results show that the polyester products obtained from glycolysis products of waste PET can be used as secondary plasticizers, with DOP for PVC.     

橡胶籽油基多元醇的制备与表征

以环氧橡胶籽油（ERSO）为原料,甲醇和异丙醇为开环试剂,氟硼酸为催化剂,制备橡胶籽油基多元醇,以产物羟值为指标对制备工艺进行了优化,并对产物进行了表征。研究结果表明,橡胶籽油基多元醇的最佳制备条件为反应时间30min,反应温度70℃,醇与ERSO的质量比为4：1,氟硼酸用量为ERSO质量的1%,异丙醇与甲醇质量比为1：1。通过验证实验可知,在此条件下制备的橡胶籽油基多元醇酸值为2.68mg/g,羟值为219.32mg/g,平均相对分子质量为870.21,含水量为0.08%,黏度为4791mPa·s。同时,通过FT-IR、¹H NMR和¹³C NMR分析表征了橡胶籽油基多元醇的化学结构,结果表明,ERSO中的环氧基发生了开环反应,生成了多元醇。     

耐低温输油软管用PVC/PUR-T共混材料研究

研究了耐低温输油软管用聚氯乙烯/热塑性聚氨酯弹性体(PVC/PUR-T)共混材料的制备。探讨了PUR-T、邻苯二甲酸二辛酯(DOP)及导电炭黑的用量对PVC/PUR-T共混材料性能的影响。结果表明,当PVC与PUR-T的配比为100∶100,DOP用量为30份、导电炭黑为10份时制成的输油软管用材料性能优异,能够满足耐低温输油软管材料的使用要求。     

An efficient plasticizer based on waste cooking oil: Structure and application

Recently, phthalates have been continuously banned in numerous fields by many countries. Therefore, the development of sustainable and efficient plasticizers has become particularly urgent. The waste cooking oil was used as the main raw materials in this study to synthesize an efficient plasticizer (acetylated-fatty acid methyl ester-trimellitic acid ester, AC-FAME-TAE). The structure of AC-FAME-TAE was characterized by FT-IR and ¹H NMR. The performance of the poly(vinyl chloride) (PVC) plasticized by AC-FAME-TAE was tested and compared with those of the PVC plasticized with di-2-ethylhexyl phthalate (DOP) and EFAME (epoxy fatty acid methyl ester), respectively. DSC results indicated that AC-FAME-TAE had excellent plasticizing efficiency for PVC. The mechanical properties of PVC plasticized by AC-FAME-TAE were as comparable as PVC plasticized by DOP from the results of tensile test. In addition, the PVC plasticized by AC-FAME-TAE had excellent thermal stability and solvent resistance by the results of leaching test and TGA.     

Studies of electrical and mechanical properties of poly(vinyl chloride) mixed with electrically conductive additives

Different samples of poly(vinyl chloride) (PVC) compositions were formulated from PVC, a polar plasticizer such as dioctylphthalate (DOP), and variable proportions of electrically conductive additives such as fast extrusion furnace (FEF) carbon black (CB), poly(vinylpyridine) (PVP), or polyacrylonitrile (PAN). Epoxidized soybean oil was added as a heat stabilizer. Samples of the PVC–CB system were also prepared by dispersing different concentrations of CB into the PVC matrix. The electrical studies showed that the addition of CB to the PVC–DOP system produces a plasticized PVC with high electrical conductivity whereas the compounding of PVC with CB produces a sample with much higher electrical conductivity. The effect of the structure of PVP and PAN on the electrical and mechanical properties of the PVC–DOP system was also studied to obtain a semiconductive plasticized PVC with good mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1590–1598, 2004     

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     

Investigations into the behaviour of “plumbonacrite” basic lead carbonate as a thermal stabiliser for polyvinyl chloride

An apparatus is described which permits reasonably uniform heat treatment of fairly large samples of PVC blends in controlled atmospheres, at preset temperatures, and for predetermined lengths of time. Experiments are described in which portions of a plasticised PVC blend, and also portions of an unplasticised PVC blend, were heated under nitrogen at 180 °C for various lengths of time up to those stages when Congo Red tests showed hydrogen chloride to be liberated. Each blend contained the basic lead carbonate “plumbonacrite”, 6PbCO₃. 3Pb(OH)₂.PbO, as stabiliser, and stearic acid as milling lubricant. Carbon dioxide evolved during the stabilising reactions was measured, and the crystalline solids in each heated PVC blend sample were studied by X-ray diffraction. The results obtained show that the plumbonacrite stabiliser in each PVC blend was used continuously and completely during the effective stabilisation period. The rates of carbon dioxide evolution were found to differ markedly between the plasticised and unplasticised blends, but in each case they could be described in terms of first order reaction kinetics. Correlation of these carbon dioxide measurements with the X-ray diffraction results led to the conclusion that the stabilising reactions in the plasticised PVC blend took place mainly in solution, whereas these reactions in the unplasticised PVC blend seemed to take place within the plumbonacrite crystals themselves. It is shown that these findings are consistent with previous work in these laboratories which has led to the idea that soluble lead compounds are formed by reaction of the basic lead stabiliser crystals with stearic acid milling lubricant, and that these compounds are in some way responsible for stabilising polyvinyl chloride against thermal decomposition. Further, it is suggested that the present results show that basic lead compounds act as thermal stabilisers for PVC in the true sense of the word. Considering in particular a radical chain mechanism for the thermal dehydrochlorination of polyvinyl chloride, a theory is proposed which explains how basic lead compounds can stabilise this polymer.     

Fracture mechanics characterisation of effects of stabilisers on creep crack growth in polyethylene pipes

Abstract

The failure behaviour of several polytheylene (PE) formulations has been characterised using linear elastic fracture mechanics (LEFM), creep crack growth (CCG) tests, and internal pressure testing. In total, six PE formulations (two polymer types with three stabiliser systems) were investigated. While no influence of stabiliser type was found in either type of polymer at high crack speeds, significant effects of the added stabiliser type and concentration were found for very low CCG rates. The experimental data also indicate good agreement between the test results of CCG experiments and the pressurised pipe tests (i.e. identical material ranking in both tests). This corroborates the hypothesis that the brittle or quasi-brittle failure of pressurised pipes can be predicted using a LEFM aproach and that CCG tests may be a useful experimental screening tool to evaluate stabiliser effectiveness.     

Effect of melt processing conditions on mechanical properties of polyvinylchloride/organoclay nanocomposites

Abstract

Polyvinylchloride compositions have been prepared by the melt intercalation method using a single screw extruder. Different types of nanofiller based on natural sodium montmorillonite were tested. In particular, intercalating agents containing amine groups combined with co-intercalating agent (low or high molecular weight plasticiser) were examined to determine which is the most suitable not only for producing the largest basal spacing and subsequently the best exfoliation of clay tactoids in polymer matrix, but also for the highest beneficial influence on mechanical properties. In the case of improved exfoliation, the effect of compounding was investigated. Therefore, three values of screw speed were studied and some blends were compounded twice to study the retention time in a single screw extruder and the influence on orientation, dispersion and exfoliation of clay particles in the PVC matrix. Moreover, the effect of different types of plasticiser on mechanical properties was also studied. Bis(2-ethylhexyl) phthalate, Bis(2-ethylhexyl) adipate and Lankroflex epoxy plasticiser were tested. Dynamical thermo-mechanical properties were examined and the tensile properties of thin PVC sheets prepared by calendaring. Using X-ray diffraction and transmission electron microscopy, it was found that partially intercalated and disordered structures arose in polyvinylchloride composites containing sodium montmorillonite, while a fine dispersion of partial exfoliation of individual montmorillonite layers in polyvinylchloride matrix was observed when this clay was organically modified. Finally, the value of the tensile modulus for PVC nanocomposites containing as little as 5 wt-% montmorillonite was increased three times provided that the optimum melt processing conditions were used.