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通过巯基与聚氯乙烯(PVC)氯原子的亲核反应将羧基引入PVC大分子链,再利用环氧脂肪酸甲酯与羧基之间的反应,通过化学键将其连接入PVC大分子链,实现对PVC内增塑.用傅里叶红外(FTIR)、核磁共振(1H-NMR)、示差扫描量热法(DSC)对改性产物进行了表征.FTIR、1H-NMR结果表明,环氧脂肪酸甲酯成功共价连接到了PVC大分子链上,接枝率为1.2 mol%;DSC测试结果显示,所采用的环氧脂肪酸甲酯改性PVC方法能有效降低PVC的玻璃化转变温度(Tg),5.6 wt%的增塑剂可将PVC的Tg从81.4℃降至37.8℃;增塑剂耐溶剂抽出性与耐挥发性实验结果表明,环氧脂肪酸甲酯在测试时间内无损失,增塑剂迁移得到彻底抑制. 相似文献
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SAN共聚物组成对PVC/ABS共混物相容性的影响 总被引:5,自引:0,他引:5
采用乳液聚合技术通过改变共聚单体的投料比(St/AN)合成了一系列不同AN结合量的ABS接枝共聚物粉料和SAN共聚物.将其与聚氯乙烯(PVC)和邻苯二甲酸二辛酯(DOP)熔融共混分别制得了PVC/ABS、PVC/SAN、PVC/ABS/DOP和PVC/SAN/DOP共混物,利用SEM、TEM和动态力学粘弹谱仪(DMA)对共混物的相容性和相结构进行了表征.结果发现,在PVC/ABS共混体系中,尽管改变接枝SAN共聚物的AN结合量,PVC和SAN共聚物均为不相容体系;在该共混物中引入增塑剂DOP后,虽然当SAN共聚物AN结合量小于23.4 wt%时,共混物在室温以上只存在一个tanδ峰,但形态结构研究结果表明共混物仍为不相容体系,共混物的相区尺寸明显地依赖于SAN共聚物中的AN结合量,当AN结合量为23.4 wt%时相区尺寸最小. 相似文献
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溶胶-凝胶富勒烯固相微萃取-气相色谱法测定塑料水浸泡液中多种邻苯二甲酸二酯 总被引:6,自引:0,他引:6
利用新型溶胶-凝胶富勒烯涂层,结合顶空固相微萃取-气相色谱法-FID检测,对PVC塑料制品在水溶液浸泡液中的12种邻苯二甲酸二酯进行了分析和测定,其检出限为0.097~3.646 μg/L;回收率为87.9%~107%;RSD<8%.对12种邻苯二甲酸二酯类增塑剂的固相微萃取条件和色谱条件进行了优化,并与商用固相微萃取聚二甲基硅氧烷(PDMS)探头的性能进行了比较.本方法应用于PVC玩具及PVC餐垫样品的分析,结果令人满意. 相似文献
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由一种新型非均相聚合方法制备的聚氯乙烯的分子结构 总被引:2,自引:0,他引:2
聚氯乙烯(PVC)树脂通常采用自由基本体聚合、悬浮聚合和乳液聚合方法制备.无链转移剂时,头-尾加成和PVC大分子自由基向单体链转移反应分别是链增长和链终止的主要方式,聚合温度成为影响PVC平均分子量及分子量分布的主要因素. 相似文献
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聚氯乙烯表面共价键合肝素及抗凝血性的研究 总被引:8,自引:0,他引:8
采用Ar等离子体引发聚乙二醇(PEG)在聚氯乙烯(PVC)表面固定化,进一步对固定PEG后的PVC进行肝素化处理,以改善PVC材料的抗凝血性能。探讨了PEG浓度对Ar等离子体固定化反应效果的影响。通过X射线光电子能谱(XPS)、衰减全反射红外光谱(ATR-FTIR)、扫描电镜(SEM)和接触角测定研究了固定PEG前后PVC的表面性能和表面形貌的变化。XPS分析证实肝素已成功地共价键合于PVC表面。采用体外凝血时间测定和血小板粘附实验对材料的抗凝血性能进行评价,结果表明,被修饰PVC材料的抗凝血性能显著提高。 相似文献
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Poly(aryl amide ether) (PAAE) thin films with nanometer-sized pores have been prepared in two steps: (1) solution casting of partially miscible poly(ethylene glycol) (PEG)/PAAE blends from one of their common solvents, dimethyl sulfoxide (DMSO), results in formation of PEG/PAAE nanocomposite films; (2) selective removal of PEG component by water washing yields nanosized, porous PAAE films. The pores have been found to have a small size variation and cover the whole surface homogeneously. With an increase in PEG contents, the sizes of the pores increase but the size distributions do not have much changes. This has been ascribed to formation of small PEG domains in PEG/PAAE composite films, which is facilitated by the strong interactions, mostly hydrogen bonds, between PEG and PAAE macromolecular chains. 相似文献
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Toshiaki Yoshioka Tomohito Kameda Masashi Ieshige Akitsugu Okuwaki 《Polymer Degradation and Stability》2008,93(10):1822-1825
Flexible poly(vinyl chloride) (PVC) was found to be dechlorinated in NaOH/ethylene glycol (EG) solution at moderate temperature and at atmospheric pressure. The degree of dechlorination increased over time with all particle sizes and with decreasing particle size. Decreased particle size resulted in an increased effective surface area, increasing the contact between the material and OH− in the NaOH/EG solution, which contributed to the high degree of dechlorination. The dechlorination of flexible PVC in NaOH/EG solution was expressed as a first-order reaction and proceeded under chemical reaction control. Diisononyl-phthalate (DINP) in the flexible PVC powder decomposed readily into phthalic acid and isononyl alcohol in a short time. For the dechlorination of the flexible PVC, the substitution (SN2) of chloride by the hydroxyl group was considered to be preferential to the elimination (E2) of hydrogen chloride. 相似文献
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Xiao-Li HeQian Zhou Xiao-Yang LiPeng Yang Johannes M.N. van Kasteren 《Polymer Degradation and Stability》2012,97(2):145-148
Highly efficient dechlorination of PVC has been realized at 180 °C and at atmospheric pressure, using 1-butyl-3-methylimidazoliumhydroxide ([Bmim]OH) as an environment-friendly reaction medium: in the absence of an external base or solvent the dechlorination efficiency is as high as 91.2%, while it is only 38.1% for PVC without ionic liquids. The dechlorination process follows first-order kinetics with apparent activation energy of 44 kJ mol−1. Mechanistic analysis provides evidence for the equilibrium presence of carbene species, together with the hydroxide ions in [Bmim]OH, thus enhancing the dechlorination of PVC via a combined elimination and substitution mechanism. 相似文献
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Poly(ethylene glycol)(PEG)‐based interpenetrating polymeric network (IPN) hydrogels were prepared for the application of enzyme immobilization. Poly(acrylamide)(PAAm) was chosen as the other network of IPN hydrogel and different concentration of PAAm networks were incorporated inside the PEG hydrogel to improve the mechanical strength and provide functional groups that covalently bind the enzyme. Formation of IPN hydrogels was confirmed by observing the weight per cent gain of hydrogel after incorporation of PAAm network and by attenuated total reflectance/Fourier transform infrared (ATR/FTIR) analysis. Synthesis of IPN hydrogels with higher PAAm content produced more crosslinked hydrogels with lower water content (WC), smaller Mc and mesh size, which resulted in enhanced mechanical properties compared to the PEG hydrogel. The IPN hydrogels exhibited tensile strength between 0.2 and 1.2 MPa while retaining high levels of hydration (70–81% water). For enzyme immobilization, glucose oxidase (GOX) was immobilized to PEG and IPN hydrogel beads. Enzyme activity studies revealed that although all the hydrogels initially had similar enzymatic activity, enzyme‐immobilizing PEG hydrogels lost most of the enzymatic activity within 2 days due to enzyme leaching while IPN hydrogels maintained a maximum 80% of the initial enzymatic activity over a week due to the covalent linkage between the enzyme and amine groups of PAAm. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Lipase-catalyzed alcoholysis between vinyl cinnamate and benzyl alcohol in fluorous solvents was investigated. This is the first report of a lipase-catalyzed reaction in a fluorous solvent. Forming the poly(ethylene glycol)(PEG)-lipase PL complex enhanced lipase activity over 16-fold over that of native lipase powder. The PEG-lipase PL complex exhibited markedly higher alcoholysis activities in fluorous solvents than in conventional organic solvents such as isooctane and n-hexane. The optimum reaction temperature for FC-77 (perfluorooctane) was 55 [degree]C and the optimum pH for the preparation of the PEG-lipase complex was 9.0; similar to the conditions for lipase PL-catalyzed reaction in aqueous solution. The alcoholysis reaction in fluorous solvent requires the addition of a FC77-miscible organic solvent (isooctane) in order to dissolve non-fluorinated substrates. Lipase activity in the fluorous solvent was significantly influenced by the volume ratio of isooctane in the reaction medium. Vinyl cinnamate inhibition of the lipase-catalyzed reaction occurred at a much lower concentration in the fluorous solvent than in isooctane. These results can be explained by the localization of substrates around lipase molecules, induced by adsorption of the substrates to the PEG layer of the PEG-lipase complex. 相似文献
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Castelletto V Krysmann MJ Clifton LA Lambourne J Noirez L 《The journal of physical chemistry. B》2007,111(38):11330-11336
In this work we report the structural characteristics of bovine serum albumin/poly(ethylene glycol) lipid conjugate (BSA/PEG(2000)-PE) complexes under physiological conditions (37 degrees C and pH 7.4) for particular fractions of BSA to PEG-lipid concentration, c(BSA)/c(PEG)(2000)-PE. Ultraviolet fluorescence spectroscopy (UV) results shown that PEG(2000)-PE is associated to BSA, leading to protein unfolding for fixed c(BSA) = 0.01 wt % and variable c(PEG)(2000)-PE = 0.0015-0.6 wt %. Tryptophan groups on the BSA surface are in contact with the PEG-lipid at c(PEG)(2000)-PE = 0.0015 wt %, while they are exposed to water at c(PEG)(2000)-PE > 0.0015 wt %. Dynamic and static light scattering (DLS and SLS) and small-angle neutron scattering (SANS) point out the existence of individual BSA/PEG-lipid complexes in the system for fixed c(BSA) = 1 wt % and variable c(PEG)(2000)-PE = 0.15-2 wt %. DLS shows that there is only one BSA molecule per protein/PEG-lipid complex, while SLS shows that the PEG-lipid associates to the BSA without promoting aggregation between adjacent protein/polymer-lipid conjugate complexes. SANS was used to show that BSA/PEG(2000)-PE complexes adopt an oblate ellipsoidal shape. Partially unfolded BSA is contained in the core of the oblate ellipsoid, which is surrounded by an external shell containing the PEG(2000)-PE. 相似文献
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以辛酸亚锡为催化剂,季戊四醇(PTOL)为引发剂,引发对二氧环己酮(PDO)单体开环聚合,合成了以PTOL为核的四臂聚对二氧环己酮(4s-PPDO).通过直接将4s-PPDO预聚物和聚乙二醇(PEG)于熔点以上、惰性气体保护下与偶联剂甲苯二异氰酸酯(TDI)交联共聚得到聚对二氧环己酮/聚乙二醇(PPDO-b-PEG)两亲性共网络聚合物(PPDO-PEG APCNs).研究了两亲性聚合物共网络结构、配比组成、溶剂种类等对聚合物溶胀率的影响,结果表明APCNs在不同类型的溶剂中表现出不同的溶胀行为,可以通过调节偶联剂的用量及PPDO/PEG的投料比来满足不同的实际需求.通过示差扫描量热分析(DSC)详细研究APCNs的结晶性能,证实交联反应降低APCNs的结晶度和结晶尺寸. 相似文献
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Poly(viny1 chloride) (PVC) was dehydrochlorinated thermally in pyridine solution under N2 atmosphere and the effect of variation of reaction time, temperature, and concentration of PVC in pyridine was studied. The extent of dehydrochlorination (or conversion, x%) increases with an increase in reaction time and temperature, and with a decrease in the concentration of PVC. Incomplete precipitation of dehydrochlorinated PVC (DHPVC) occurs by nonsolvent (methanol). During dehydrochlorination there is no HCl evolution as it forms a pyridine hydrochloride complex which is supposed to act as a catalyst for dehydrochlorination. A possible mechanism has been proposed. Chain scission and cross-linking reactions are responsible for the molecular weight changes that take place during the reaction. 相似文献