Thermal Decomposition of Polymer Mixtures Containing Poly(vinyl chloride)

Thermal decomposition of a series of 1 : 1 mixtures of typical polymer waste materials [polyethylene (PE), poly(propylene) (PP), polystyrene (PS), polyacrylonitrile (PAN), polyisoprene, poly(methyl methacrylate) (PMMA), polyamide‐6 (PA‐6), polyamide‐12 (PA‐12), polyamide‐6,6 (PA‐6,6), and poly(1,4‐phenylene terephthalamide) (Kevlar)] with poly(vinyl chloride) (PVC) was examined using thermal analysis and analytical pyrolysis techniques. It was found that the presence of polyamides and PAN promotes the dehydrochlorination of PVC, but PVC has no effect on the main decomposition temperature of polyamides. The hydrogen chloride evolution from PVC is not altered when other vinyl polymers or polyolefins are present. The thermal degradation of PAN is retarded significantly, whereas that of the other vinyl polymers is shifted to a slightly higher temperature in the presence of PVC. Among the pyrolysis products of PAN‐PVC mixture methyl chloride was found in comparable amount to the other gaseous products at 500°C pyrolysis temperature.     

氯化氢生产中新技术的应用

介绍了青岛海晶化工集团有限公司自动设计的3万t/a（31%盐酸，单套）合成氯化氢装置，该装置具有工艺流程短，采用敝开式钢框架结构，设备材质优良，单套产量大，采用DCS控制，远距离输送氯化氢气体等特点，2000年4月至2001年12月，共生产工业酸盐和高纯盐酸5.1万t，为PVC输送氯化氢气体量折合成31%盐酸共11万t，特别适用于配套电石法生产PVC。     

降低聚氯乙烯电缆料在燃烧时氯化氢释放量的方法探讨

详细介绍了聚氯乙烯电缆料在燃烧时降低氯化氢释放量的方法 :(1)加入酸吸收剂 ;(2 )提高酸吸收剂的吸收效率 ,减少颗粒度或改善其表面活性 ;(3)降低聚氯乙烯燃烧时氯化氢的释放速度 ;(4)减少氯化氢的产生源。并从理论上逐个进行了分析 ,并进行了相应的实验室验证     

The stabilisation of PVC: A study of the reaction of dry hydrogen chloride with white lead suspended in hot mineral oil

The reaction of dry hydrogen chloride with a suspension of white lead in hot mineral oil (MO) has been studied by withdrawing samples and examining the solids by X-ray powder diffraction (XRPD). The white lead basic lead carbonate was slowly converted into tribasic lead chloride, which itself reacted to form “basic lead chloride X”, and this was finally converted into normal lead chloride. Similarities between this reaction sequence and that observed when plumbonacrite (another basic lead carbonate) was used as a thermal stabiliser in an unplasticised polyvinyl chloride (PVC) blend indicate that this plumbonacrite behaved to a large extent as a scavenger for hydrogen chloride produced by thermal decomposition of the polymer. However, it is suggested that true stabilisation (by free radical exchange reactions which retard thermal decomposition of the polymer) may also take place to varying extents in rigid (unplasticised) PVC blends, depending on the formation and mobility of intermediate stabilising species (the most effective of which seem to be the lead compounds of organic acids). This behaviour is different from that in plasticised materials where true stabilisation seems to be the dominant reaction. XRPD data are tabulated for the uncharacterised “basic lead chloride X”.     

液相电导法测定氯化氢脱析速率

介绍了采用液相电导法测定氯化氢脱析速率,从而测试聚氯乙烯树脂稳定性的方法,该方法能提供PVC树脂脱HCl的诱导期、降解速率及降解全过程的信息,与刚果红和老化白度法相比,能确切地反映树脂的热稳定性。     

Blends of poly(vinyl chloride) with plasticized polyaniline

A series of poly(vinyl chloride) (PVC)/polyaniline (PANI) blends plasticized and protonated simulataneously by bis(2-ethylhexyl) hydrogen phosphate, bis(4-nitrophenyl) phosphate, diphenyl phosphate, or dibenzyl phosphate was prepared by a mass homogenization technique. Thermal analysis studies by means of thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed that PVC/PANI blends with bis(2-ethylhexyl) hydrogen phosphate were characterized by the highest thermal stability values. Kinetic analysis of the decomposition process by the isoconversional Friedman method showed that the activation energy did not change substantially over the broad conversion range; further advanced kinetic analysis by a nonlinear regression method revealed that the kinetic function that was the best approximation for the experimental data was based on a reaction of nth order.     

A study of the reaction of dry hydrogen chloride with white lead suspended in di—2—ethyl hexyl phthalate at 182 °C

In order to test certain ideas which have recently been formulated on the way in which basic lead compounds stabilise polyvinyl chloride against thermal decomposition, the reaction of dry hydrogen chloride with a suspension of white lead in hot di-2-ethyl hexyl phthalate was studied by withdrawing samples and examining the solids by X-ray diffraction. Normal lead phthalate, and an uncharacterised substance which has been called “basic lead chloride X”, were formed initially. Subsequently, this basic lead chloride X was converted to normal lead chloride. The continuous formation of normal lead phthalate in this experiment contrasts with observations made on the crystalline products of stabilising reactions in PVC blends containing basic lead carbonates, and suggests that there are fundamental differences between the reaction mechanisms which prevail in these two systems. It is proposed that the results obtained with PVC blends are best explained in terms of free-radical mechanisms for thermal decomposition and stabilisation of this polymer, whereas the results obtained in the present experiment can be explained by a simple acid—base type reaction. X-ray powder diffraction data are tabulated for normal lead phthalate.     

Hydrogen chloride evolution from the heating of poly(vinyl chloride) compounds

The dehydrochlorination and the thermal decomposition of five PVC materials was studied using two techniques: a batch analytical method, combining ion chromatography and atomic absorption and continuous thermogravimetry. The temperatures studied ranged from 60°C to 120°C, over a period of almost one year (50 weeks). It was found that a very large proportion of the soluble chloride emitted early on by the PVC materials into the liquid phase is not hydrogen chloride. None of the five materials tested emitted significant amounts of HCl at temperatures lower than 105°C. The emissions at 90°C after 50 weeks ranged from <0.01 Φg/g to 23.62 Φg/g. Furthermore, one of the materials tested emitted virtually no HCl, even at 105°C, as the amount of HCl measured was almost indistinguishable from the normal background of the analytical instruments (37.30 Φg/g after 50 weeks). Numerical calculations of kinetic reaction rates and extrapolation of the results to use temperatures (40°C) indicate that properly stabilized PVC compounds will be unlikely to lose 1% of the mass of PVC as HCl until 2 billion years have passed. This number has no physical meaning as such and may be incorrect by a vast margin, but it clearly indicates that a 1% loss of HCl is unlikely to occur during the useful lifetime of a commercial product into which the PVC material has been fabricated. This is a conservative estimate, which ignores the much higher activation energy for dehydrochlorination at temperatures below the glass transition temperature (ca. 85°C). Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and some properties of anthracene and anthraquinone incorporated poly(vinyl chloride) and the ion exchange resin therefrom

Poly(vinyl chloride) has been modified by chlorine displacement reaction with 2-anthrol and anthraquinone-2-ol. The condensates (PVC-ACOL and PVC-AQOL) are insoluble in all solvents common to PVC and have been characterized by elemental and IR spectra analysis. The initial decomposition temperature of these condensates follow the trend: PVC-AQOL (250°C) > PVC-ACOL (200°C) > PVC(190°C) and the overall thermal stabilities beyond 60% decomposition follows the same trend. Permittivity and dielectric loss of these condensates sharply fall with increasing applied frequency (10–1.3 ×10⁷ Hz) to a limiting constant value. In contrast, for unmodified PVC these values are low and remain independent of frequency in the same range. Sulfonation of these PVC condensates affords a weak acid resin with ? COOH and ? OH ionogenic groups, but no strong sulfonic acid groups due presumably to oxidative degradation of the PVC matrix.     

Synthesis and application of a novel thermostable epoxy plasticizer based on levulinic acid for poly(vinyl chloride)

Epoxy bisphenol acid isooctyl ester (EBAIE) was synthesized and characterized by FTIR and H-NMR. EBAIE was used as poly(vinyl chloride) (PVC) plasticizer for the first time, and its addition amount was 30 wt% of PVC. The mechanical properties, thermal stability, compatibility, and decomposition activation energy of PVC blends were systematically studied. Compared to the commercial plasticizer-dioctyl phthalate (DOP), the tensile strength had been significantly increased from 30.64 to 45.07 MPa, while the elongation at break had little difference. The thermal stability analysis showed that the static stability time at 180°C had been extended from 40 to 300 min. The decomposition activation energy indicated that the EBAIE plasticized PVC was with a higher thermal stability. The extraction and volatility resistance of the novel plasticizer were superior to those of DOP.     

聚氯乙烯生产中的氯化氢循环回收技术及应用

简述我国聚氯乙烯(PVC)生产高速发展形势及尚存问题,指出传统氯化氢回收技术的弊病所在,阐明以组合塔为核心设备的氯化氢循环回收技术及其优越性,介绍组合塔及其制作技术发展的各项措施,简要回顾以新技术替代传统技术从粗氯乙烯气体中回收氯化氢的10年改革进程、效果和在国内17个省的37套装置中的应用概况。     

Thermal analysis of irradiated poly(vinyl chloride)

The thermal decomposition and resultant disposal of waste poly(vinyl chloride) (PVC) is facilitated by preliminary exposure to ionizing radiation, such as energetic electrons, in an oxygen atmosphere. The results of isothermal and temperature-programmed thermogravimetry, differential thermal analysis, and effluent gas analysis in nitrogen and in oxygen indicate that the major effect of irradiation is to render PVC increasingly susceptible to oxidation. The presence of oxygen during heating enhances the decomposition. Crystalline order in PVC is destroyed by irradiation.     

3D打印用聚氯乙烯多相复合体系的开发

采用高分子类增塑剂乙烯-乙酸乙烯酯共聚物(EVM)替代聚氯乙烯(PVC)传统增塑剂,制备出具有双连续相结构的PVC/EVM/聚乳酸(PLA)共混物.通过热分析、流变学测试及微观形貌观察等研究了共混物结构与性能间的关系.结果表明,随着填料蒙脱土(OMMT)或碳纳米管的加入,PVC/EVM/PLA共混物的热分解温度和体系燃...     

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。     

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.     

K2SO4装置副产高纯度HCl在PVC生产中的应用

介绍了齐化集团有限公司K2SO4装置的工艺流程,阐述了K2SO4副产高纯度HCl用于PVC生产上的优点,分析了高纯度HCl给PVC企业带来的经济效益和社会效益。结果表明:K2SO4装置所输送的HCl纯度高,可使齐化集团有限公司8万t/a PVC装置增产2 402．6t/a,减少了合成工序尾气处理的负荷,有利于PVC装置的安全运行。     

一种新型蓖麻油酸季戊四醇酯的制备及应用

用季戊四醇和蓖麻油酸通过酯化反应反应制备了蓖麻油季戊四醇酯。采用红外光谱仪和核磁共振仪对制备的产品的化学结构进行表征。并将其作为增塑剂与聚氯乙烯（PVC）共混,研究了塑化PVC的平衡扭矩、热性能和力学性能,对该增塑剂在不同溶媒中的耐迁移性进行了研究,并与邻苯二甲酸二辛酯和环氧大豆油的塑化性能进行了对比。结果表明,蓖麻油季戊四醇酯塑化PVC的加工平衡扭矩为14.9 N·m,改善了PVC的加工稳定性;塑化PVC的拉伸强度为23.28 MPa,断裂伸长率为263.13 %,耐迁移性能较邻苯二甲酸酯和环氧豆油较好,可以作为PVC增塑剂使用。     

液氯液化尾气合成氯化氢生产氯乙烯

对液化尾氯的应用进行了可行性探索,通过对液化尾氯的生产数据分析,并从理论计算上求证,证明氯气液化尾氯合成氯化氢直供电石法PVC生产是安全可行的。     

Poly(ethylene glycol)–polyhedral oligomeric silsesquioxane as a novel plasticizer and thermal stabilizer for poly(vinyl chloride) nanocomposites

The plasticizing and thermostabilizing effect of poly(ethylene glycol)–polyhedral oligomeric silsesquioxane (PEG‐POSS) on poly(vinyl chloride) (PVC) is discussed thoroughly in this work. As PEG‐POSS content increases, PVC becomes more flexible and the decomposition temperature of PVC increases slightly. Meanwhile, the temperature of maximum HCl emission is elevated from 265.3 °C in neat PVC to 285.7 °C in PVC nanocomposites, with the peak intensity of HCl emission decreased by 30.8%, and a new lower intensity of HCl emission peak appearing at much higher temperature (around 370 °C), which is in accordance with the maximum degradation temperature of PEG‐POSS. Thereby, a possible dehydrochlorination mechanism is suggested according to the fact that the electron donor effect of ether groups would stabilize the C? Cl bonds by means of more electron cloud stacked in those bonds, which agrees with Fourier transform infrared and X‐ray photoelectron spectroscopy experiments in terms of hydrogen bonds. © 2016 Society of Chemical Industry     

纳米水滑石对PVC热稳定性和烟密度的影响

研究了纳米水滑石（nano—HT）对聚氯乙烯（PVC）热稳定性和燃烧烟密度的影响。采用原位聚合并熔融加工得到PVC／纳米水滑石复合材料，纳米水滑石在PVC基体中分散均匀，分散尺度小于100nm。随着纳米水滑石含量增加，PVC／nano—HT复合材料的热分解温度和刚果红变色时间增加，热稳定性提高；分散均匀的纳米水滑石对PVC具有良好的抑烟效果，当PVC／nano—HT复合材料中纳米水滑石含量为1．25％和2．5％时，最大烟密度分别比空白PVC低40％和60％左右。