Metal soaps of wool wax acids as stabilizers for plasticized polyvinyl chloride

Copper, magnesium, lead, nickel, cobalt, manganese, iron, chromium, cadmium, and barium soaps of the wool wax acid fraction have been tested as stabilizers for plasticized polyvinyl chloride polymers. Barium, cadmium, and lead soaps performed well in the light stability evaluations. In the heat aging tests barium, magnesium, lead, and nickel soaps were superior while cadmium, and manganese soaps performed poorly. The copper, cobalt, iron, and chromium soaps were ineffective. Two tests for stability were employed: an accelerated light aging test and an accelerated heat aging test. Combinations of barium and cadmium soaps were tested for synergistic effects and found to be more effective as stabilizers than the individual soaps. Soaps made from fractions of acids by partitioning the whole wool wax acid fraction were also tested. Neither the hydroxy nor the non-hydroxy acid fraction soaps had as goad stabilizing properties for PVC as those of the whole acid fraction. Presented at the Spring Meeting of the American Oil Chemists' Society, St. Louis, Missouri, May 1–3, 1961. Eastern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Investigation of lanthanum trioxypurine with zinc stearate and pentaerythritol as complex thermal stabilizers for poly(vinyl chloride)

Lanthanum trioxypurine (LaTr) was triumphantly synthesized by reacting trioxypurine and lanthanum nitrate at neutral condition and was characterized by elemental analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The thermal stability effect of LaTr with its assistant thermal stabilizers about zinc stearate (ZnSt₂) and pentaerythritol (Pe) on poly(vinyl chloride) (PVC) was investigated by Congo red test, discoloration test, UV–vis spectroscopy test, and thermal decomposition kinetics. The results showed that the addition of LaTr as thermal stabilizer could significantly enhance static stability time and long‐term stability of PVC. It could be mainly attributed to the anions in the structure of LaTr, could efficiently absorb the hydrogen chloride released by PVC, and have ability to replace unstable chlorine atoms on structure of PVC. Moreover, the mixing of LaTr, Pe, and ZnSt₂ could reveal an excellent synergistic effect and both promote the initial color and the long‐term thermal stability of PVC. The thermal stability of PVC reached the optimal state when the ratio of LaTr/Pe/ZnSt₂ was 1.8/0.6/0.6. In addition, compared with the reaction energy E_a and UV–vis spectroscopy test's result of PVC samples, the order of PVC's thermal stability was PVC/LaTr/Pe/ZnSt₂ > PVC/LaTr/Pe > PVC/LaTr. The result was further ascertained that LaTr/Pe/ZnSt₂ showed excellent synergistic effect and could be used as an excellent complex thermal stabilizer for PVC. J. VINYL ADDIT. TECHNOL., 25:347–358, 2019. © 2019 Society of Plastics Engineers     

新型高效有机热稳定剂

聚氯乙烯及氯化石蜡等有机卤代物,由于其本身的结构缺陷,在受热使用过程中,会发生分解反应,产生卤化氢,导致卤代物的破坏和加工设备的损坏等严重后果,因此卤代物在受热使用过程中必须添加热稳定剂,以防止卤化氢及进一步的不利结果产生。传统的热稳定剂一般都含有有毒重金属,使用受到极大的限制,因此研究和开发新型无毒热稳定剂,特别是有机热稳定剂是稳定剂发展的重要方向。论文根据传统的热稳定机理,首先通过刚果红实验筛选本身具有较好热稳定性或具有协同热稳定作用的多元醇类化合物为先导物,再采用结构修饰的方法,对选取的多元醇进行酯化和醚化修饰,引入具有稳定活性的环氧基团和增加与PVC相溶性和分散性的酯基或醚键基团,并且对这些结构修饰物进行稳定性能的考察,得到了稳定性和应用性能更优的三甘醇二缩水甘油醚、甘油三缩水甘油醚和双酚A二缩水甘油醚等多元醇衍生物,为有机热稳定剂的深入研究提供了参考。     

Synergism in thermal stabilization of polyvinyl chloride

Plasticized polyvinyl chloride was thermally stabilized by barium, cadmium, and zinc laurates, epoxidized soybean oil, and monoalkyl diaryl phosphite, and by combinations of these stabilizers. Of 26 possible combinations, 18 showed some improvement, 8 showed useful improvement, 7 showed marked improvement, and 3 systems were outstanding. Of the 26 combinations, 10 showed distinct synergism, based mainly upon combinations of Group II-B metals with Group II-A metals, “secondary” stabilizers, or both. Combinations of Group II-B metals with “secondary” stabilizers were particularly interesting and promising.     

Influence of processing conditions on the leaching of thermal stabilizers from plasticized polyvinyl chloride in the presence of water

Plasticized PVC formulations for pharmaceutical packaging contain calcium and zinc stearates, which are PVC heat stabilizers. It was found in the literature that these additives can migrate to some aqueous solutions, especially when the pH is alkaline, the best example being sodium bicarbonate solutions. So, the aim of this work was to demonstrate the correlation between the lubricant ability of these stearates and their further migration in fluids. For this purpose, we studied the migration of calcium and zinc stearates during an extrusion step, focusing essentially on slip phenomenon. We have demonstrated here that slip phenomenon occurs in the case of plasticized PVC heat stabilized by calcium and zinc stearates. The slip phenomenon amplitude increases with the total amount of stearates in the formulation and also when the extrusion temperature decreases. The analysis of a die insert through scanning electron microscopy coupled with an X-ray energy dispersive technique could allow us to see that the additive mainly responsible for the slip is calcium stearate. The analysis of the leachable components of the formulations migrating after steam sterilization in sodium bicarbonate solutions leads to conclude that zinc stearate also migrates to the metal surface of the die during extrusion, but in a lower extent than calcium stearate. So, a good correlation exists between the processing conditions, including essentially the stearate concentration and the extrusion temperature, and the migration of these additives from the extruded sample to aqueous solutions. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2391–2400, 1998     

Lanthanum histidine with pentaerythritol and zinc stearate as thermal stabilizers for poly(vinyl chloride)

Lanthanum histidine [La(His)₂·(NO₃)·2H₂O or La(His)₂] was synthesized via the reaction of histidine and lanthanum nitrate, and it was investigated as a stabilizer for poly(vinyl chloride) (PVC). The results show that La(His)₂ exhibited a stabilizing effect on PVC as a long‐term stabilizer because it prolonged the stability time of PVC to 76 min, which was about 24 times longer than the stability time of the pure PVC. The stabilizing effect of La(His)₂ as a costabilizer with pentaerythritol (Pe) and zinc stearate (ZnSt₂) was also studied. The results show that the use of La(His)₂ with Pe or Pe/ZnSt₂ improved the stability time of PVC. La(His)₂/Pe/ZnSt₂ provided PVC with a good initial color and long‐term stability, and when it was prepared at mass ratios of 0.8:2.4:0.8 and 1.6:1.6:0.8, the stability times of PVC were improved to 86 and 88 min, respectively. As a nontoxic stabilizer, La(His)₂/Pe/ZnSt₂ has the potential to replace the toxic stabilizers widely used in PVC manufacturing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42878.     

Study on lanthanum‐pentaerythritol alkoxide as a thermal stabilizer for rigid polyvinyl chloride

Lanthanum‐pentaerythritol (La‐PE) alkoxide, a polyol‐based metal alkoxide, had been synthesized and used as a thermal stabilizer for polyvinylchloride (PVC) . Thermogravimetric (TG), differential thermal analysis (DTG), mass spectrum (MS), and Fourier transform infrared (FTIR) spectroscopy were used to confirm the synthesis reaction. The thermal stability of rigid PVC stabilized with La‐PE was tested by means of the Congo Red test, conductivity test, thermal aging test, thermal gravimetric analysis (TGA), and UV‐visible (UV‐vis) spectroscopy. The results showed that addition of La‐PE could significantly prolong static stability time of PVC and increase the apparent activation energy for degradation reaction. The oven aging test showed that La‐PE could improve the initial color of PVC. Moreover, addition of La‐PE could significantly reduce the concentrations of the conjugated double bonds of PVC and reduce weight loss . The possible thermal stability mechanism had also been discussed. Besides having good ability to neutralize hydrochloric acid (HCl), La‐PE could substitute or inactivate the labile chlorine atoms in the PVC chains. J. VINYL ADDIT. TECHNOL., 23:55–61, 2017. © 2015 Society of Plastics Engineers     

Vernolic acid esters as plasticizers for polyvinyl chloride

The methyl, propyl, butyl, isobutyl, hexyl, cyclohexyl, octyl, and 2-ethylhexyl esters of vernolic (epoxyoleic) acid, a naturally-occurring epoxy acid, were prepared and evaluated as plasticizers of polyvinyl chloride. All the esters showed good compatibility. The data indicated that they are excellent low temperature plasticizers having T_f temperatures below −50C. They also have the added advantage of greatly increasing the heat stability of the polyvinyl chloride and improving the light stability. The results are compared with DOP and other epoxy-containing plasticizers now being used commercially. These esters should not only be useful as primary plasticizers but also in combination with other plasticizers as plasticizer-stabilizers. Presented at the AOCS Meeting. Cineinnati, October 1965 E. Utiliz. Res. Dev. Div., ARS, USDA.     

Effect of relatively nontoxic thermal stabilizers on photodegradation of poly(vinyl chloride)

The influence of relatively nontoxic thermal stabilizers including different types of organic calcium complex (Ca/Zn system of liquid stabilizers) and organotin on photodegradation of poly(vinyl chloride) (PVC) was investigated by color difference measurement, viscosity‐average molecular weight determination, UV–vis spectroscopy, Fourier transform infrared (FTIR), and thermogravimetric (TG) analysis. PVC films containing relatively nontoxic thermal stabilizers were prepared by solution casting and then exposed to xenon‐arc light source with the irradiance of 0.51 W/(m²·nm) at 65°C. Two major chain processes, photodehydrochlorination and photo‐oxidation, occur simultaneously during photodegradation of PVC. It has been confirmed by both color difference and UV–vis spectra that during the former 300 h of irradiation, organic calcium complex stabilizers retard photodehydrochlorination as well as initial color development of PVC films while organotin stabilizers remarkably accelerate photodehydrochlorination after 100 h. Relative carbonyl index (RCI) is first introduced to the analysis of FTIR results, which implies that organotin has a better ability to inhibit photo‐oxidation than organic calcium complex and ensures longer stabilization time. The antioxidation of mercaptan organotin has been observed because it is an effective decomposer of peroxides and hydroperoxides. TG analysis reveals that some unstable structures generated due to the irradiation of ultraviolet can easily split away off from PVC macromolecular backbones under relatively low temperature. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Mechanism of action and effectiveness of ester thiols as thermal stabilizers for poly(vinyl chloride)

Organic thiols containing at least one carboxylate ester group (ester thiols) are excellent thermal stabilizers for both rigid and plasticized poly(vinyl chloride) (PVC). Their mechanism of action is shown to involve the deactivation of unstable structural defects by nucleophilic chloride displacement, the retardation and removal of coloration through thiol additions to polyene double bonds, and the prevention of autoacceleration during thermal dehydrochlorination through polyene shortening reactions and the scavenging of free radicals formed from polyenes and HCl. An unusually facile displacement of labile chloride that is favored by thiol acidity can account, at least in part, for the relatively high effectiveness of dipentaerythritol hexakis(mercaptoacetate) as a stabilizer. J. VINYL ADDIT. TECHNOL., 13:170–175, 2007. © 2007 Society of Plastics Engineers     

Metal formates as potential stabilizers for vinylidene chloride copolymers

Vinylidene chloride copolymers have a number of superior properties, most notably, a high barrier to the transport of oxygen and other small molecules. As a consequence, these materials have assumed a position of prominence in the packaging industry. At processing temperatures these copolymers tend to undergo degradative dehydrochlorination. The dehydrochlorination reaction is a typical chain process with distinct initiation, propagation, and termination phases. It has been demonstrated that initiation of degradation is strongly facilitated by the presence of unsaturation along the backbone. Such unsaturation may be introduced via interaction of the polymer with a variety of agents which might commonly be encountered during polymerization or processing. The presence of an unsaturated unit within the polymer generates an allylic dichloromethylene, which may function as a major defect (labile) site for the initiation of degradation. The conversion of these dichloromethylene units into nonreactive groups would interrupt propagation of the dehydrochlorination reaction and lead to the stabilization of the copolymer. Potential stabilization in the presence of metal formates has been examined using a vinylidene chloride/methyl acrylate (5 mol%) copolymer and thermogravimetric techniques. The effect of the metal formate on the stability of the polymer reflects the relative halogenophilicity of the metal cation present. Metal formates of low cation acidity [sodium, calcium, nickel(II) and to a lesser extent lead(II), cadmium, manganese(II) and magnesium] may be expected to be ineffective as stabilizers for vinylidene chloride copolymers. At the other extreme, metal formates that contain cations sufficiently acidic to actively strip chlorine from the polymer backbone, e.g., zinc formate, will function to enhance the degradation process. An effective carboxylate stabilizer must contain a metal cation sufficiently acidic to interact with allylic chlorine and to facilitate its displacement by the carboxylate anion. Copper(II) formate may possess the balance of cation acidity and carboxylate acitvity to function as an effective stabilizer for vinylidene chloride copolymers.     

N-substituted maleimides as thermal stabilizers for rigid polyvinylchloride

N-substituted maleimides have been investigated as thermal stabilizers for rigid polyvinylchloride (PVC) at 180°C in air by measuring the rate of dehydrochlorination and the extent of discoloration of the polymer. The results reveal the higher stabilizing efficiency of these products relative to basic lead carbonate, dibutyl tin maleate, and cadmium-barium stearate stabilizers commonly used in industry. The induction period (Ts) increases as a function of the positive resonance effect of the substituents (+R). Moreover, the investigated stabilizers impart better color stability for the degraded samples as compared with the stearate stabilizer. The stabilizer efficiencies are attributed to their radical trapping potency which intervenes with the radical degradation process of PVC, while the good color stability is due to the ability of the stabilizer to interact with the conjugated double bonds formed on the PVC chains as a result of degradation. A mechanism illustrating the stabilizer's action is proposed.     

Effect of thermal stabilizers on the photo-oxidative degradation of solid poly(vinyl chloride)

It has been found that metal (Ba, Ca, Cd and Pb) stearates and pure stearic acid have stabilizing effects on the photodehydrochlorination of poly(vinyl chloride) (PVC) and the formation of polyene structures. On the other hand the same compounds accelerate photo-oxidation of PVC. From oxygen uptake measurements at different temperatures we calculated the energy of activation of photo-oxidation. It was found that metal stearates decrease the energy of activation of photo-oxidation processes of PVC, whereas stearic acid increases it. A synergistic effect of an equimolecular mixture of Ba and Cd stearates has also been observed.     

小分子有机化合物对聚氯乙烯结晶度的影响

通过傅里叶转换红外光谱、差示扫描量热法及广角X射线衍射法研究了乙酰苯胺、己二酸和邻苯二甲酸氢钾与聚氯乙烯(PVC)的相容性及对聚氯乙烯结晶度的影响。研究结果表明,各添加剂均与PVC有一定相容性,但己二酸与PVC的相容性较小。乙酰苯胺、己二酸和邻苯二甲酸氢钾可以使PVC结晶度增大。混合体系中PVC结晶相的分子链均为平面锯齿状构型。乙酰苯胺和己二酸可以增大PVC无定形相的分子链构象的稳定性,而邻苯二甲酸氢钾则使无定形相分子链构象稳定性减小。三者对PVC的晶型无影响,均为正交晶系。     

Phenyl urea derivatives as organic stabilizers for rigid poly(vinyl chloride) against photo‐degradation

Phenyl urea derivatives have been prepared and investigated as photostabilizers for rigid PVC by measuring the extent of weight loss (%), the amount of gel formation as well as the intrinsic viscosity of the soluble fractions of the degraded polymer. Moreover, the efficiency of these stabilizers was evaluated from the extent of discoloration of the degraded polymer in their presence. The results indicated a reasonable stabilizing effect of these derivatives when compared with the commercially used UV stabilizers: phenyl salicylate (Salol) and methanone, 2‐hydroxy‐4‐(octyloxy)‐phenyl‐benzophenone. A synergistic effect is achieved when the phenyl urea derivatives are mixed with the UV absorbers in the ratio (75 : 25%), respectively. A radical mechanism is proposed to account for the stabilizing action of the products investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2217–2226, 2007     

Feasibility study of water as thinner for polyvinyl chloride plastisol

In the traditional formula of polyvinyl chloride (PVC) gloves, the diluent of PVC plastisol is usually organic solvent, which causes serious environmental pollution during the molding process. The aim of this study was to develop a low viscosity PVC plastisol emulsion (PDE) using water as a thinner by blending PVC emulsion (PVCE) with diisononyl phthalate (DINP) emulsion. DINP emulsion (DINPE) was prepared by a compound emulsifier of polyoxyethylene octyl phenol ether-10 and sorbitan monooleate. The effects of compound emulsifier concentration on the stability and microstructure of DINPE were investigated. The results showed that the optimal compound emulsifier concentration of DINPE was 10 wt%. In addition, the PDE obtained by blending exhibited a relatively uniform unimodal droplet size distribution. The steady state data revealed that the emulsions were shear-thinning pseudoplastic liquid. The effect of solid content and temperature on the apparent viscosity of PDE were also evaluated. The mechanical spectra obtained suggested the presence of weak gel structure in the PDE. The mechanical test results showed that the tensile strength and elongation at break of PVC film obtained by PDE were 12.62 MPa and 310.31%, respectively. This study demonstrated that water was effective in reducing the viscosity of PVC plastisol, which would promote the application of water thinner in glove production.     

三聚氰胺氰尿酸盐对聚酰胺6热降解行为的影响

用热失重(TGA和DTG)、差示扫描量热分析(DSC)等热分析手段和傅立叶红外光谱(FTIR)研究了三聚氰胺氰尿酸盐MC对PA6热降解性能的影响和作用本质。结果表明,MC降低了PA6的热稳定性,改变了PA6的热降解途径,促进了PA6的分解。MC分解形成的三聚氰胺可进一步凝缩成热稳定性较高的三嗪类物质,此物质在凝缩相中也具有一定的阻燃作用。而MC主要以吸热的方式在凝缩相分解区和气相反应区发挥阻燃作用。     

Synthesis and evaluation of epoxidized vegetable oleic acid as a novel environmental benign plasticizer for polyvinyl chloride

A bio-based plasticizers, acetyl-oleate triethylene glycol (AOT), was successfully synthesized by using oleic acid as a raw material through esterification, epoxidation, and acetylation. Its structure was analyzed by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance. The plasticizing performances of this plasticizer was compared with those of two commercial ones: dioctyl terephthalate (DOTP) and dioctyl adipate (DOA). This was done by blending these plasticizers with PVC, respectively. Thermal gravimetric analysis results showed that the 5% weight loss temperature of PVC with AOT was 53°C higher than that of DOA and 36°C higher than that of DOTP. The tensile results showed that the AOT plasticized PVC had excellent stretchability: its elongation at break with 50 phr AOT reached 697.7%. Furthermore, its transmittance was as high as 90%, showing better compatibility of ATO with PVC.