羧酸酯稀土对聚氯乙烯的热氧稳定作用

用热烘法研究了羧酸酯稀土对聚氯乙烯的热氧稳定作用。借助于富里叶变换红外光谱分析，通过跟踪羰基基团在热老化过程中的变化，比较ＣＥＲＥＳ与有机锡及两者的复合稳定剂对ＰＶＣ的热氧稳定性能。     

乙酰乙基纤维素的热致液晶性能及其与PA6原位复合的研究

将乙基纤维素乙酰化制备乙酰乙基纤维素。用ＮＭＲ，ＩＲ测定了ＡＥＣ的乙酰取代度，用ＤＳＣ，ＨＳＰＬＭ研究了ＡＥＣ的热致液晶性能，织构与Ａ－ＤＳ的关系。在此基础上研究了ＰＡ６／ＡＥＣ原位复合单丝的形态结构和力学性能，证明一定条件下ＡＥＣ对ＰＡ６有明显增强作用，总取代度增大是主要作用机制。     

热作模具钢热疲劳性能与铝液腐蚀性能研究

对４Ｃｒ５ＭｏＳｉＶ１钢和３Ｃｒ２Ｗ８Ｖ钢分别进行３ＳＮＣ－ＲＥ共渗加氧化、ＳＮＣ共渗加氧化和ＳＮＣ－ＲＥ共渗等表面处理，并对经处理的试样分别进行了热疲劳性能和铝液腐蚀性能试验研究。     

羧酸酯稀土对聚氯乙烯凝胶化的促进作用

用示差量热扫描研究了羧酸酯稀土对聚氯乙烯的凝胶化过程。研究表明ＣＥＲＥＳ有促进ＰＶＣ凝胶化的作用。基于分子轨道理论推测了ＣＥＲＥＳ与ＰＶＣ大分子之间可能存在的作用力，探索了ＣＥＲＥＳ促进ＰＶＣ凝胶化的机理。     

PSF／CaCO3复合材料的性能研究

采用双螺杆挤出机制备ＰＳＦ／ＣａＣＯ３复合材料，从而研究其复合组份与性能的关系。研究结果表明：ＰＳＥ／ＣａＣＯ３复合材料部分力学性能与热性能比ＰＳＦ树脂有所提高。     

羧酸酯稀土对聚氯乙烯的光老化稳定作用

用人工老化的方法比较了羧酸酯稀土和有机锡对聚氯乙烯（ＰＶＣ）的光老化稳定作用。借助于红外光谱和紫外／可见光谱，通过跟踪光老化过程中羰基基团和共轭双键的变化，发现羧酸酯稀土的抗脱ＨＣｌ能力优于有机锡，但抗氧化能力不如有机锡。     

纳米SiC—Si3N4复合粉体的制备及研究

本文以炭黑和气凝氧化硅为原料，采用碳热还原氮化的方法制备纳米ＳｉＣ－Ｓｉ３Ｎ４复合粉体；复合粉中ＳｉＣ的含量由起始粉中Ｃ：ＳｉＯ２的摩尔比控制。在复合粉体的表征中用ＸＲＤ线宽法测量ＳｉＣ粒径大小。ＴＥＭ照片显示Ｓｉ３Ｎ４粒径在１００￣２００ｎｍ；ＳｉＣ为纳米级。文中还对生成复合粉体的反应机理进行了探讨。同时利用这一工艺制备出单相的Ｓｉ３Ｎ４粉和ＳｉＣ粉。     

纳米SiC－Si_3N_4复合粉体的制备及研究

本文以炭黑和气凝氧化硅为原料，采用碳热还原氨化的方法制备纳米ＳｉＣ－Ｓｉ３Ｎ４复合粉体；复合粉中ＳｉＣ的含量由起始粉中Ｃ：ＳｉＯ２的摩尔比控制．在复合粉体的表征中用ＸＲＤ线宽法测量ＳｉＣ粒径大小．ＴＥＭ照片显示Ｓｉ３Ｎ４粒径在１００～２００ｎｍ；ＳｉＣ为纳米级．文中还对生成复合粉体的反应机理进行了探讨．同时利用这一工艺制备出单相的Ｓｉ３Ｎ４粉和ＳｉＣ粉．     

电沉积RE-Ni-W-P-SiC多功能复合材料的抗高温氧化性研究*

研究了ＲＥ－Ｎｉ－Ｗ－Ｐ－ＳｉＣ多功能复合材料高温氧化性能,结果表明,在高温氧化过程中,纯镍镀层、Ｎｉ－Ｗ－Ｐ、Ｎｉ－Ｗ－Ｐ－ＳｉＣ和ＲＥ－Ｎｉ－Ｗ－Ｐ－ＳｉＣ复合镀层的氧化膜质量和氧化时间的关系呈混合型曲线,即直线和曲线复合的规律。在氧化时间小于６０ｍｉｎ时,氧化膜的增长规律近似于直线方程;而在氧化时间大于６０ｍｉｎ时,氧化膜的增长规律近似于直线方程;而在氧化时间大于６０ｍｉｎ后,它的增长规律可以用幂函数方程表示。４种镀层氧化速率的大小顺序是Ｎｉ〉Ｎｉ－Ｗ－Ｐ〉Ｎｉ－Ｗ－Ｐ－ＳｉＣ〉ＲＥ－Ｎｉ－Ｗ－Ｐ－ＳｉＣ。Ｎｉ－Ｗ－Ｐ、Ｎｉ－Ｗ－Ｐ－ＳｉＣ和ＲＥ－Ｎｉ－Ｗ－Ｐ３种镀层的氧化膜质量随着氧化温度的升高而呈指数型增加。ＲＥ－Ｎｉ－Ｗ－Ｐ－ＳｉＣ复合镀层与Ｎｉ－Ｗ－Ｐ合金层相比,它的高温抗氧化性能可以提高２～３倍     

层状Mg-Al复合金属氢氧化物对PVC静态和动态热稳定性的影响

采用热重分析法(TG)、转矩流变仪法研究了水滑石类层状Mg/Al复合金属氢氧化物(LDHs)对硬质和软质聚氯乙烯(PVC)静态、动态热稳定性的作用.TG研究结果表明,与单一LDHs相比,LDHs/Sn复合稳定剂对硬质PVC有较好的协同稳定作用,显著提高了PVC的热稳定性.转矩流变仪研究结果发现,PVC/LDHs/Sn复配体系中有机锡比率增加,硬质PVC动态热稳定时间增加较明显,热稳定性提高显著.LDHs用作软质PVC热稳定剂时,稳定效果优于Ba-Zn液体复合稳定剂.     

Polyvinyl chloride and its organotin stabilizers with special reference to packaging materials and commodities: A review

Polyvinyl Chloride (PVC) is a thermoplastic that has entered practically all areas of life as a cheap and versatile material. Since PVC also fulfils the high quality requirements placed on modern packaging materials, with respect to packaging techniques and consumer protection, it is being used to an increasing extent for packaging of food and beverages as well as pharmaceutical and cosmetic products. The various additives required for processing PVC into packaging materials and commodity articles, as well as improving its properties during usage (e.g. lubricants and stabilizers), are harmless with regard to human and ecotoxicological aspects. Their use is non-hazardous and is therefore permitted by authorities. In the group of thermo- and light stabilizers for PVC, mixtures of mono- and dialkyltin thioglycolates play a major role. In accordance with legislation, these are allowed to be used in rigid PVC. In addition to their excellent stabilizing effect, they are not hazardous to the health of consumers of products packed in rigid PVC. Similarly, no health hazards exist to personnel, working in PVC production and processing plants, from volatile components of organotin stabilizers provided that processing and environmental prerequisites of modern technology are observed. The disposal of household waste that contains used PVC materials — stabilized with mixtures of mono- and dialkyltin thioglycolates — does not cause additional difficulties.     

Electron beam damage of some chlorine containing polymers and PVC blends

The electron beam damage of PVC, PVDC, chlorinated PE, chlorosulphonated PE (Hypalon) and chloroendic acid polyester has been studied by chlorine loss and mass loss measurements. The mass loss decay curves have been recalculated for true mass loss and correlated with the X-ray measurements of chlorine loss. It is shown that the major mechanism of degradation in these polymers is dehydrochlorination. The rate of dehydrochlorination is dependent on the chemical structure of the polymer, and in particular on the availability of hydrogen for HCl formation. However, in case of chloroendic acid polyester, more complicated volatile chlorinated compounds are also formed. The dehydrochlorination rate and mass loss of miscible PVC blends, namely PVC with organotin stabilizer, PMMA, PCL and SAN have been studied. The rate of chlorine loss from PVC was found to be unchanged for all blends except for PMMA and PCL, where it slightly increased due to the chemical reaction between the molecular fragments of both polymers. The differences between the thermal degradation and electron beam damage are also discussed.     

Comparison Studies on the Percolation Thresholds of Binary Mixture Tablets Containing Excipients of Plastic/Brittle and Plastic/Plastic Deformation Properties

Percolation theory has been used with great interest in understanding the design and characterization of dosage forms. In this study, work has been carried out to investigate the behavior of binary mixture tablets containing excipients of similar and different deformation properties. The binary mixture tablets were prepared by direct compression using lactose, polyvinyl chloride (PVC), Eudragit RS 100, and microcrystalline cellulose (MCC). The application of percolation theory on the relationships between compactibility, P_max, or compression susceptibility (compressibility), γ, and mixture compositions reveals the presence of percolation thresholds even for mixtures of similar deformation properties. The results showed that all mixture compositions exhibited at least one discreet change in the slope, which was referred to as the percolation threshold. The PVC/Eudragit RS100 mixture compositions showed significant percolation threshold at 80% (w/w) PVC loading. Two percolation thresholds were observed from a series of binary mixtures containing similar plastic deformation materials (PVC/MCC). The percolation thresholds were determined at 20% (w/w) and 80% (w/w) PVC loading. These are areas where one of the components percolates throughout the system and the properties of the tablets are expected to experience a sudden change. Experimental results, however, showed that total disruption of the tablet physical properties at the specified percolation thresholds can be observed for PVC/lactose mixtures at 20–30% (w/w) loading while only minor changes in the tablets' strength for PVC/MCC or PVC/Eudragit RS 100 mixtures were observed.     

Comparison studies on the percolation thresholds of binary mixture tablets containing excipients of plastic/brittle and plastic/plastic deformation properties

Percolation theory has been used with great interest in understanding the design and characterization of dosage forms. In this study, work has been carried out to investigate the behavior of binary mixture tablets containing excipients of similar and different deformation properties. The binary mixture tablets were prepared by direct compression using lactose, polyvinyl chloride (PVC), Eudragit RS 100, and microcrystalline cellulose (MCC). The application of percolation theory on the relationships between compactibility, P_max, or compression susceptibility (compressibility), γ, and mixture compositions reveals the presence of percolation thresholds even for mixtures of similar deformation properties. The results showed that all mixture compositions exhibited at least one discreet change in the slope, which was referred to as the percolation threshold. The PVC/Eudragit RS100 mixture compositions showed significant percolation threshold at 80% (w/w) PVC loading. Two percolation thresholds were observed from a series of binary mixtures containing similar plastic deformation materials (PVC/MCC). The percolation thresholds were determined at 20% (w/w) and 80% (w/w) PVC loading. These are areas where one of the components percolates throughout the system and the properties of the tablets are expected to experience a sudden change. Experimental results, however, showed that total disruption of the tablet physical properties at the specified percolation thresholds can be observed for PVC/lactose mixtures at 20-30% (w/w) loading while only minor changes in the tablets' strength for PVC/MCC or PVC/Eudragit RS 100 mixtures were observed.     

PVC/阻燃抑烟剂体系的力化学改性

研究了高能振磨作用对PVC／硼酸锌(ZB),PVC／三氧化二锑(Sb2O3)-三氧化钼(MoO3)以及PVC／Sb2O3-MoO3-ZB体系阻燃抑烟性能和力学性能的影响。结果表明,高能振磨可使PVC与ZB、Sb2O3或MoO3分子闯产生化学键合,增强了PVC基体与阻燃抑烟荆ZB,Sb2O3-MoO3,Sb2O3-MoO3-ZB之同的界面相互作用,促进了阻燃抑烟荆(FRs)在PVC中的分散,使PVC／FRs体系的烟密度(Dm)值降低,极限氧指数(LOI)值以及抗冲击强度,拉伸强度,断裂伸长率得到明显提高。     

聚氯乙烯/聚丙烯酸丁酯-白泥纳米复合材料的冲击断面形态及流变性能

通过多步交换反应及扩散-聚合的方法,使聚丙烯酸丁酯(PBA)嵌入到改性层状结构的白泥层间,得到白泥-聚丙烯酸丁酯(PBA)纳米复合物的微米级粒子;然后将聚氯乙烯与白泥-聚丙烯酸丁酯进行熔融共混,制得具有一定特性的有机-无机纳米复合材料;并对复合材料的缺口冲击断面形态及流变性能进行了研究。结果表明,复合材料的冲击断面具有明显的网状结构和空洞化特征,属典型的韧性断裂;PVC/白泥-PBA(质量分数0.5%~7.0%)纳米复合材料基本上保持了纯PVC的加工性能。     

SnO_2/聚氯乙烯复合材料的制备及光催化性能研究

以二氯化亚锡和聚氯乙烯(PVC)为主要原料,通过光化学合成的方法,在低功率紫外灯辐照下制备了复合光催化剂的前驱体,经热处理后得到了含有共轭聚合物结构的SnO2/聚氯乙烯复合光催化剂材料,并用XRD和UV-Vis等对复合材料进行了表征。光催化降解亚甲基蓝的实验表明,复合材料在可见光辐照下能有效地降解亚甲基蓝,复合材料的催化活性明显优于纯SnO2和PVC直接热处理产物。     

Poly(ethylene glycol) enhanced dehydrochlorination of poly(vinyl chloride)

Poly(ethylene glycol) (PEG), an environment-friendly reaction medium, has been adopted to accelerate the dehydrochlorination of poly(vinyl chloride) (PVC). Experimental results demonstrated that at 210 degrees C for 1h the dechlorination degree was as high as 74.2% for PVC/PEG, while for PVC only 50.0%. Moreover, from thermogravimetric analysis, it was found that for PVC/PEG the decomposition of PVC corresponding to the dehydrochlorination stage shifted to lower temperatures compared with that of pure PVC, suggesting some interactions exist between PEG and PVC that caused the faster dehydrochlorination rate. In addition, during this process, no waste byproducts such as KCl have been produced, and satisfactory recyclability of PEG (10 cycles) has been obtained.     

应力作用下硬质聚氯乙烯的紫外光老化机理

研究了聚氯乙烯(PVC)在应力作用下的紫外光老化行为.老化后的样品采用超薄切片法,应用红外和紫外光谱分析手段,从微观角度研究了应力对PVC各层化学结构变化的影响;同时对样品的凝胶含量和表面形貌等进行了表征,探讨了应力作用下PvC的紫外光老化机理.结果表明:应力使PVC的氧化层增厚,共轭双键层变薄;应力的存在会大大加速氧化反应,但却降低了共轭双键的生成量.