二元羧酸单酯金属盐对PVC的热稳定作用——性能递变规律与机理

用烘箱变色法测试了丙二酸、丁二酸和马来酸单丁酯的钙、锶、钡、锌和镉盐对聚氯乙烯（PVC）热稳定性的影响。结果表明,二元羧酸单酯金属盐所稳定PVC的变色随其分子中羧酸根羰基C原子的正电性和金属离子的极化力的增强而减慢,而分子中含有亲双烯结构的二元羧酸单酯金属盐所稳定的PVC的着色减轻;据此可以推知,二元羧酸单酯金属盐之所以能抑制PVC的变色,并不是因为能取代不稳定氯（Frye和Horst机理）,而是因为能以羧酸根羰基 C 原子和金属离子与 PVC 发生亲电反应,而之所以分子中含有亲双烯结构的二元羧酸单酯金属盐所稳定的PVC着色减轻,则是因为它们还能与PVC发生Diels-Alder环加成反应。     

Mold susceptibility of rigid PVC/wood‐flour composites

Rigid PVC/wood‐flour composite lumber containing either hardwood (maple) or a softwood (southern pine) wood flour at different levels of wood‐flour content was evaluated for susceptibility to fungal colonization and discoloration by using standard tests that mimicked exterior (ASTM G21) and interior (ASTM D3273) environments, respectively. In the exterior test protocol, although both types of PVC/wood‐flour composite lumber exhibited fungal colonization and discoloration, the composites containing maple exhibited greater discoloration than those containing pine. Irrespective of wood species, fungal colonization and discoloration in the composite lumber were greater at the bottom faces where they were in constant contact with moisture. The wood content range (50–100 phr) used in this study showed no effect on extent of fungal colonization and discoloration. All composites showed no discoloration in the interior test protocol. Both optical microscopy and environmental scanning electron microscopy clearly demonstrated that wood flour particulates are not completely encapsulated by the PVC matrix, so that exposed wood flour in the surface crevices of the composite lumber may serve as points of moisture sorption and staging points for fungal colonization and discoloration. J. Vinyl Addit. Technol. 10:179–186, 2004. © 2004 Society of Plastics Engineers.     

Stabilization of poly(vinyl chloride). VIII. Synergisms between epoxy compounds and metal soaps

Effects of bisphenol A type epoxy compounds involving various average molecular weights on the zinc stearate/calcium stearate and the cadmium stearate/barium stearate synergetic soaps induced thermal stabilization of poly(vinyl chloride) (PVC) were investigated by colorimetry. The remarkable stabilization effects of epoxides could not be observed on the PVC films without synergetic soaps, while the stabilization of PVC was markedly enhanced by combined use of epoxides and synergetic soaps. The appearance of excessive coloration of cool color producing metal chloride–polyene complexes which were an origin of abrupt discoloration of stabilized PVC was retarded by using epoxides together with synergetic soaps. Moreover, as for PVC with or without synergetic soaps, the epoxy compounds did not inhibit the formation of longer polyene chains which were a chromophore for yellow orange of aged PVC. Further colorimetries and IR or X-ray photoelectron spectroscopies on the various PVC containing epoxy compounds and zinc chloride indicated that the epoxy groups caught the zinc chloride. The synergetic effect between epoxy compounds and synergetic metal soaps is ascribed to the action that the epoxides serve as an acceptor for the excessive cool color producing metal chloride produced from zinc stearate and cadmium stearate to retard the abrupt discoloration of stabilized PVC.     

二元羧酸有机锡对聚氯乙烯的热稳定作用——性能递变规律与机理

用烘箱变色法测试了几种二元羧酸二烷基锡对聚氯乙烯（PVC）的热稳定作用。结果表明,其热稳定性能随分子中羧酸根羰基C原子正电性的增强而提高;如果分子中含有亲双烯结构单元,则其所稳定的PVC试片在最终黑化前呈现较轻的着色;二元羧酸二烷基锡是通过其带正电荷的羧酸根羰基C原子和（或）二烷基锡离子作为亲电中心与PVC发生亲电反应（简称亲电反应机理）对PVC产生热稳定作用;而如果分子中含有亲双烯结构单元,则同时以亲电反应和Diels-Alder反应机理发挥热稳定作用,但前者为主而后者为辅。     

Diamide derivatives as photostabilizers for plasticized poly(vinyl chloride)

Some diamide derivatives have been prepared, characterized, and investigated as photostabilizers for plasticized poly(vinyl chloride) (PVC), containing dioctyl phthalate and dibutyl phthalate in a concentration of 30% by weight of the polymer. The stabilizing efficiency of the prepared diamides was evaluated by determining the weight loss percentage that resulted from HCl evolution during the photodegradation process. Moreover, the efficiency was evaluated by determining the amount of gel formed as well as the intrinsic viscosity of the soluble fractions of the photodegraded polymer. The extent of discoloration of the photodegraded stabilized and plasticized PVC was also investigated. The stabilization mechanism and the effect of plasticizers on the photostability of PVC are discussed. J. Vinyl Addit. Technol., 2008. © 2008 Society of Plastics Engineers     

Synergistic profiles of chain‐breaking antioxidants with phosphites and hindered amine light stabilizers in styrene–ethylene–butadiene–styrene (SEBS) block copolymer

The photostabilization of poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) (SEBS) by phosphite/p‐hydroxybenzoate antioxidants and hindered phenol/hindered amine light stabilizers (HALS) was studied by using a variety of spectroscopic methods, including FTIR, UV, and luminescence spectroscopy coupled with crosslinking and hydroperoxide analysis. The results were compared with those obtained for hindered phenols and their combinations with phosphite antioxidants. All the stabilizing packages stabilized the SEBS in terms of the inhibition of discoloration and the formation of hydroperoxides, acetophenone, and oxidation products, as well as chain scission and disaggregation of the styrene units. Although phosphite/p‐hydroxybenzoate combinations appeared to reduce the formation of oxidation products, they did not show any remarkable enhancement in long‐term stabilization with respect to phenolic/phosphite antioxidants. On the other hand, strong synergistic profiles were found with the HALS. Mobility and diffusion impediments in the polymeric material appeared to play an important role in the stabilizing activity of the HALS. J. VINYL. ADDIT. TECHNOL. 12:8–13, 2006. © 2006 Society of Plastics Engineers     

Photostabilizing efficiency of ultraviolet light stabilizers for rigid poly(vinyl chloride) against photo‐oxidation

The photostabilizing efficiency of different light stabilizers in poly(vinyl chloride) (PVC) was investigated by discoloration, ultraviolet (UV) reflection experiment, Fourier transform infrared spectrum (FTIR), and scanning electron microscopy (SEM). The results show that the addition of light stabilizers can slow down discoloration of PVC. The UV reflection results verify that this change is due to the distribution of light stabilizers on irradiated surfaces, which can absorb (such as organic stabilizers) or reflect (such as titanium dioxide) UV light differently. The order of stabilizers that can slower the extent of discoloration is titanium dioxide (TiO₂) > Tinuvin 234 (U4) > XT 833 (H2), U4 > Tinuvin 531 (U3) > Chimassorb 944 (H1), phenyl salicylate (U1). FTIR results show that the carbonyl group of pure PVC, TiO₂, and H1‐doped PVC increases significantly, indicating that the photo‐oxidation reactions of these irradiated samples are relatively serious. The SEM results show that the surface damages of PVC doped with U2, U4, and H2 are somehow slighter, with only small holes or cavities on the surface, whereas the surfaces of pure PVC and H1‐doped PVC are full of big and deep holes and some holes or cavities of 10 μm are detected. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Stabilization of poly(vinyl chloride). X. Synergisms between epoxidized polybutadienes and metal soaps on the stabilization of poly(vinyl chloride)

Effects of epoxidized 1,2- or 1,4-polybutadienes on the zinc stearate/calcium stearate synergetic soap-induced thermal stabilization of poly(vinyl chloride) (PVC) were investigated by colorimetry. The remarkable stabilization effects of epoxidized polybutadienes could not be observed on the PVC films without synergetic soaps, while the stabilization of PVC was markedly enhanced by combined use of epoxidized polybutadienes with synergetic soaps. Excessive coloration of cool color-producing zinc chloride-polyene complexes that were the source of abrupt discoloration of stabilized PVC was retarded by using epoxidized polybutadienes together with synergetic soap. The synergism of epoxidized polybutadienes was enhanced with increasing epoxy contents. Moreover, the effect is also clearly dependent on degree of dispersion of epoxidized polybutadienes in PVC. Further colorimetries, infrared (IR), and X-ray photoelectron spectroscopies on the various PVC-containing epoxidized polybutadienes and zinc chloride indicated that the epoxy groups capture the zinc chloride. The synergistic effect between epoxidized polybutadienes and metal soap was ascribed to epoxidized polybutadienes serving as acceptors for the excessive cool color-producing zinc chloride produced by zinc stearate to retard the abrupt discoloration of stabilized PVC. The plate-out phenomenon appeared during the molding process of PVC-containing epoxy compounds was considerably retarded by epoxidized polybutadienes which modified polyols. The polyol-modifying epoxidized polybutadienes also exhibited a marked effect on PVC stabilization with metal soap.     

热稳定剂对PVC塑料异型材变色因素的影响

稳定剂是能防止或抑制PVC树脂在成型和使用过程中由于光、热、氧和机械作用而引起的分解的物质。本文通过热稳定剂的作用机理、主要性能等的论述,指出了常用热稳定剂对PVC塑料异型材变色的影响,最后指出了发展绿色环境保型稳定剂应注意的一些事项。     

Influence of acrylate processing aid‐based ionomer containing lanthanide (La(III)) ion on thermal stability,fusion, transparency and mechanical properties of rigid poly(vinyl chloride)

An acrylate processing aid (ACR)‐based ionomer containing lanthanide (La(III)) ion was synthesized and the influences of the ionomer on thermal stability, fusion time, transparency and tensile properties of rigid poly(vinyl chloride) (PVC) were investigated. Results revealed that the ionomer with a suitable La(III) content behaved as a good stabilizer as well as processing aid to the rigid PVC product. The ionomer could accelerate fusion of PVC much more quickly than ACR because of the strong interaction between La(III) carboxylate and PVC. Moreover, it exhibited a stabilizing efficiency comparable to lanthanum and calcium stearates (LaSt₃ and CaSt₂). The composite stabilizer of ionomer/zinc stearate (ZnSt₂) exhibited an ability to improve initial discoloration better than LaSt₃/ZnSt₂ and CaSt₂/ZnSt₂ because the ionomer could form a complex with ZnSt₂ much more slowly than LaSt₃ and CaSt₂. The compounds stabilized using ionomer/ZnSt₂ exhibited a transparency comparable to those stabilized using organotin or liquid barium/zinc stabilizers, which was much better than those stabilized using LaSt₃/ZnSt₂ and CaSt₂/ZnSt₂. Copyright © 2011 Society of Chemical Industry     

Thermal degradation behavior of poly(vinyl chloride) in presence of poly(N‐acryloyl‐N′‐cyanoacetohydrazide)

The thermal degradation behavior of poly (vinyl chloride), PVC, in presence of poly(N‐acryloyl‐N′‐cyanoacetohydrazide), PACAH, has been studied using continuous potentiometric determination of the evolved HCl gas from the degradation process from one hand and by measuring the extent of discoloration of the degraded samples from the other. The efficiency of blending PACAH with dibasic lead carbonate, DBLC, conventional thermal stabilizer has also been investigated. A probable radical mechanism for the effect of PACAH on the thermal stabilization of PVC has been proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Zum mechanismus der thermischen abspaltung von chlorwasserstoff aus polyvinylchlorid. 5. Mitt.: Über die verteilung der polyensequenzlängen in thermisch abgebauten technischen polyvinylchloriden und in anwesenheit stabilisierend wirkender substanzen

The rates of dehydrochlorination of commercial poly (vinyl chlorides) and the distribution of the lengths of the resulting polyene sequences may vary widely depending on the origin of the polymer. – In the presence of diphenyllead dichloride the rate of dehydrochlorination is increased, while the resulting discoloration is less intense compared to that of pure poly (vinyl chloride) because of a shift of the polyene sequence lengths distribution. Genuine stabilizers, on the other hand, effect retardation in dehydrochlorination as well as a shift of the sequence lengths distribution towards shorter polyene sequences. The causes for this behavior of admixed stabilizers using lead and cadmium octoate as examples as well as of internally stabilized PVC are discussed.     

Photostability,thermal and mechanical properties of poly(vinyl chloride)/novel acrylate terpolymer blend

Methyl methacrylate/2‐hydroxyethyl methacrylate/maleic anhydride terpolymer with various compositions was synthesized, characterized and investigated as a photostabilizer for rigid polyvinyl chloride (PVC). The chemical structure of the terpolymer MMA/HEMA/MA, was confirmed by ultraviolet–visible and FTIR, spectroscopy. The molecular weights of the terpolymer were determined by applying gel permeation chromatography. The stabilizing efficiency of the terpolymer was evaluated by the determination of the weight loss of PVC/terpolymer blends after various irradiation times. The content of the formed gel as well as the intrinsic viscosity of the soluble fraction of the photodegraded polymer were also determined. The efficiency was also evaluated by measuring the extent of the discoloration of the photodegraded polymer. Thermal gravimetric analysis of the terpolymer and PVC/terpolymer blend were measured. Moreover, physicomechanical properties of photodegraded stabilized PVC samples were as well measured. The results revealed that the photostabilizing efficiency as well as thermal stability increased in the presence of the terpolymer as blended with PVC and by the increase of maleic anhydride ratio in the terpolymer. The photostabilizing efficiencies were compared with the industrially known UV absorber 2‐hydroxy‐4‐(octyloxy) phenylbenzophenone. J. VINYL ADDIT. TECHNOL., 25:E55–E62, 2019. © 2018 Society of Plastics Engineers     

外墙乳胶漆耐候性研究

采用天然曝晒和人工老化方法研究了各种纯丙乳液和硅丙乳液的耐候性,由该类乳液制备的不同PVC白色乳胶漆的耐候性,以及白色乳胶漆与各色色浆配制的浅色乳胶漆的耐候性。结果表明:硅丙乳液和核壳型纯丙乳液具有较好的耐候性,高PVC乳胶漆容易变色,炭黑和氧化铁系色浆适合于配制浅色外墙乳胶漆,有机颜料色浆应用在外墙时应谨慎。     

Processing thermal stability and degradation kinetics of poly(vinyl chloride)/montmorillonite composites

Thermal stability of polyvinyl chloride (PVC) based montmorillonite composites with either sodium montmorillonite (MMT) or alkyl ammonium ion modified montmorillonite (OMMT) were investigated by thermogravimetric analysis. The apparent activation energies associated with the first thermal degradation stage were calculated by the methods of Flynn–Wall–Ozawa and Kissinger in nitrogen atmosphere at several different heating rates. The processing thermal stability of PVC and PVC/MMT(OMMT) composites was also discussed. Increase of mixing torque did not result in a larger intercalation extent of PVC on MMT; instead, it unexpectedly induced discoloration of PVC and then deteriorated the processing stability, especially in the presence of OMMT. The apparent activation energies in the first thermal degradation stage exhibited little difference among PVC, PVC/MMT, and PVC/OMMT composites, and the kinetic compensation effect of S_p^* kept a constant value, indicating that the thermal stability and thermal degradation mechanism of PVC were not affected by the presence of either MMT or OMMT, although the processing discoloration of PVC is observed for PVC/OMMT composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1521–1526, 2004     

N′‐acryloyl benzhydrazide as a thermal stabilizer for rigid poly(vinyl chloride)

N′‐Acryloyl benzhydrazide (ABH) was examined as a thermal stabilizer and costabilizer for rigid poly(vinyl chloride) (PVC) in air at 180°C. Its high stabilizing efficiency was shown by its high thermal stability value (T_s) when compared with those of two common reference stabilizers used industrially, dibasic lead carbonate (DBLC) and a calcium–zinc soap. Blending this organic stabilizer with the reference stabilizers in different ratios had synergistic effects on both the thermal stability and the extent of discoloration of the PVC. The Ni²⁺ complex of ABH gave better thermal stability and lesser discoloration than the parent organic stabilizer. Also, blending that complex with DBLC in different ratios gave better stability and lower discoloration. Thermogravimetric analysis confirmed the improved stability of PVC in the presence of the ABH stabilizer. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.     

抗氧剂对汽车内饰用PVC人造革光稳定性能的影响

比较了4种抗氧剂对汽车内饰用PVC人造革耐光级数的影响;研究了使用不同抗氧剂时,金红石钛白色浆的用量对汽车内饰用PVC人造革耐光级数的影响。结果表明：①多酚类抗氧剂DCPDstyreneL比单酚类及双酚类抗氧剂的抗光老化能力好;②在试验配方下,金红石钛白色浆可提高PVC人造革的光稳定性能;③抗氧剂1010和抗氧剂168并用时具有协同效应。     

Accelerated ultraviolet weathering of PVC/wood‐flour composites

Ultraviolet weathering performance of polyvinyl chloride (PVC) filled with different concentrations of wood flour was studied. Extruded PVC/wood‐flour composite samples were subjected to cyclic ultraviolet lamps/condensation exposures and assessed over a total of 400 and 2600 hours. Each assessment consisted of DRIFTFTIR and XPS collections, contact angle measurement, color measurement, and tensile property testing. The experimental results indicated that wood flours are effective chromophore materials since their incorporation into a rigid PVC matrix accelerated the degradation of the polymeric matrix. Photodegradation converted unfilled PVC samples to a colored material of lower extensibility. Although composite samples exhibited greater discoloration than unfilled PVC samples, they retained all their original strength and stiffness properties even after 2600 hours of cyclic UV irradiation/condensation exposures.     

Stabilization of poly(vinyl chloride). III. Synergism between metal soaps and masking agents on the stabilization of poly(vinyl chloride)

The stabilization mechanism by synergetic metal soaps containing complementary colors was previously reported. With increased heating times, the color of heated poly(vinyl chloride) (PVC) films containing Cd/Ba and Zn/Ca synergetic soaps markedly deviated from the polyene color. These color deviations usually decreased the thermal stability of PVC. Discoloration from polyene color to blue appeared especially on PVC films containing Zn/Ca synergetic soap and was concomitant with a marked decrease in thermal stability. The stabilization of PVC containing synergetic metal soaps can be improved by masking or removing the excessive color. In this work, the addition of various masking agents, such as ethylenediaminetetraacetic acid, o-phenanthroline, triethanolamine, urea, N,N′ -dimethylolurea, melamine, stearylamide, and lactams, to PVC containing synergetic metal soaps was investigated. It was shown that these masking agents do markedly slow down the discoloration of PVC.     

A study of the processing characteristics and mechanical properties of multiple recycled rigid PVC

This study focuses on the ability of U‐PVC to be processed a number of times. Three different types of U‐PVC were investigated: virgin lead‐stabilized material; virgin calcium/zinc‐stabilized material; and reground, 20‐year‐old, post‐consumer windows. Each material was extruded four times, without any addition of any stabilizers. Samples were taken at each stage for rheological and mechanical analysis. J. Vinyl Addit. Technol. 10:174–178, 2004. © 2004 Society of Plastics Engineers.