三嵌段共聚物PS-b-PEG-b-PS与聚苯乙烯共混薄膜的表面形貌与性能研究

使用原子转移自由基聚合(ATRP)制备三嵌段共聚物PS-b-PEG-b-PS.通过红外光谱、核磁共振氢谱(1H-NMR)和凝胶渗透色谱(GPC)对嵌段共聚物结构及分子量进行表征.将嵌段共聚物与聚苯乙烯溶液共混成膜,使用原子力显微镜(AFM)和接触角测试仪(CA)对不同含量嵌段共聚物共混膜的表面形貌和性能进行了分析表征.PEG链段与PS链段在共混膜中发生了微相分离,由于PEG链段对PS链段的热力学排斥作用以及PS的硬链段特性,PS不能在PEG微区上方形成覆盖,因而在薄膜表面形成大量孔洞,PEG微相区位于孔洞底部.随嵌段共聚物含量增加,孔洞(PEG微区)尺寸增大.当嵌段共聚物含量增加10％以后,孔洞内出现PS微相区,导致形成“胞状”结构.嵌段共聚物含量增加使得共混薄膜的亲水性和表面张力增大.     

PLA-b-PEG共聚物膜的制备与性能研究

使乳酸(LA)和数均相对分子量2000的聚乙二醇(PEG)在180℃下的二甲苯中进行溶液缩聚,制得了聚乳酸-聚乙二醇嵌段(PLA-b-PEG)共聚物,PLA-b-PEG的分子量随反应时间的延长而增大,分子量分布保持在较窄的范围内;改变LA与PEG的投料比,可将PLA-b-PEG嵌段共聚物的玻璃化转变温度控制在35.6~54.3℃,有利于室温下膜的形成以及膜性能的稳定。采用铸膜法制得了透明的PLA-b-PEG共聚物膜,用动态接触角测试表明,随着PEG的增加接触角减小、亲水性增大,可望应用于生物医学材料领域。     

不同拓扑结构PEG-PCL嵌段共聚物的结晶研究

合成了不同拓扑结构的聚乙二醇-聚己内酯(PEG-PCL)嵌段共聚物,共聚物结构分别为AB型线性两嵌段(diblock)、ABA型线性三嵌段(triblock)、AB_2型星形(star shape)嵌段共聚物。通过表征发现嵌段共聚物的分子量与设计的分子量接近,且相对分子量分布窄。通过XRD、DSC、热台偏光显微镜(HSPOM)研究了拓扑结构对共聚物结晶的影响。ABA聚合物中间的PEG亲水链受到两端PCL链段阻碍,其结晶衍射峰最弱。三者的等温结晶速率按AB、AB_2、ABA的速率递减,形成的球晶结构规整度则逐渐增加。     

PA6基永久抗静电材料的制备与表征

以己内酰胺和聚乙二醇(PEG)为原料,采用熔融缩聚法制备了PA6基抗静电共聚物(PA6-PEG)。通过傅里叶变换红外光谱(FTIR)、核磁共振(NMR)、热失重分析(TGA)对产物的结构和热性能进行表征,并测试了抗静电性能。结果表明:PA6和PEG之间发生了酯化反应,软硬段通过酯基连接形成共聚物;PEG的加入能够有效地降低PA6的表面电阻率;PA6-PEG共聚物的热分解温度约为350℃,具有良好的热稳定性。     

PET工程塑料的研制

通过共缩聚反应合成了不同PEG分子量的PET-PEG共聚脂,采用DSC法测定了共聚物的结晶性能、结晶速度.还测试了共聚物的力学性能.结果表明:PEG的加入能有效地增加分子链柔性,改善结晶性能,其中PET-PEG 6000在100℃的半结晶时间为0.7min.PEG的含量在20%以下,拉伸性能没有恶化,冲击强度、断裂伸长率大大提高.     

对生物降解聚合物PBS共聚改性的研究

采用不同官能团如苯二甲酸(TA)、聚乙二醇(PEG,Mn=1000)对聚丁二酸丁二醇酯(PBS)主链进行共聚改性,得到了基于PBS的均聚共聚物PBST;嵌段共聚物PBES。利用1H-NMR、GPC、WXRD、热分析、拉力试验对共聚物的化学结构、相对分子质量、结晶性、热性能及力学性质的影响进行了研究。结果表明:将TA、PEG引入PBS的主链,在较短时间内得到了数均分子质量约5万的无规PBST和嵌段PBES共聚物;PEG的介入使聚合物的结晶度降低、断裂伸长率大幅度增加,最大达846.4%;TA的介入则使其结晶度增加,断裂伸长率呈逐渐减小的趋势,但仍比PBS有所增大;两种聚合物均有良好的热稳定性。     

低温增韧尼龙6的制备与研究

采用阴离子淤浆聚合方法进行了已内酰胺与不同分子量聚乙二醇的共聚合成,产物具有良好的成型加工性能.材料性能测试实验表明:共聚物具有优良的低温韧性,同时具有较好的热性能和拉伸性能,材料的结晶结构易于通过加工条件和热处理进行调控.     

H型两亲性嵌段共聚物的合成与表征

以聚乙二醇(PEG-400)、环氧氯丙烷为原料,氢氧化钾为缚酸剂,十六烷基三甲基溴化铵为相转移催化剂制得聚乙二醇缩水甘油醚(epoxide-PEG-epoxide).然后,在氢氧化钠水溶液中,聚乙二醇缩水甘油醚中的环氧键水解生成分子链两端各含有两个羟基的大分子引发剂((HO)2PEG(OH)2).最终,以辛酸亚锡为催化剂,端羟基大分子引发剂引发ε-己内酯开环聚合,合成了不同相对分子质量的H型两亲性嵌段共聚物((PCL)2PEG(PCL)2).通过红外光谱(FTIR)和核磁共振氢谱(1H-NMR),聚乙二醇缩水甘油醚,端羟基大分子引发剂和H型两亲性嵌段共聚物的结构得到了确认.示差扫描量热法对两亲性嵌段共聚物热性能的研究表明:当亲水段的聚乙二醇分子量为400时,聚合物的熔融温度主要受疏水段的聚己内酯影响,随着聚己内酯链段长度的增加,熔融温度升高.     

聚乙二醇对氯化聚氯乙烯超滤膜微观结构及其性能的影响

探讨了聚乙二醇(PEG)及其分子量对氯化聚氯乙烯(CPVC)铸膜液黏度及其超滤膜微观结构和性能(纯水通量、截留率、机械性能和耐污染性能)的影响。结果表明,随着PEG分子量的增大,CPVC铸膜液黏度增大,CPVC超滤膜表面由网络大孔结构变为致密结构,PEG400和600对CPVC超滤膜断面微观结构没有太大影响,仍然保持海绵状结构,PEG相对分子质量超过1 000以后,CPVC超滤膜断面变为指状大孔结构与皮层构成非对称结构。铸膜液中添加PEG后,CPVC超滤膜纯水通量大幅度上升,但是截留率有不同程度的下降;随着PEG分子量的增大,CPVC超滤膜的纯水通量,耐污染性能及截留率均呈上升趋势。综合比较,PEG600作为添加剂,CPVC超滤膜能获得较好的性能。     

N-对甲苯基马来酰亚胺与丙烯腈共聚动力学及共聚物的热性能

以AIBN为引发剂,研究了不同配比的丙烯腈(AN)与N-对甲苯基马来酰亚胺(NPTMI)在80℃的自由基溶液共聚合 ,并根据FTIR谱图确证了共聚物的存在。根据元素分析的结果,用FR法得到竞聚率的值rAN=0.57,rNPTMI=1.47。用GPC测定了共聚物的分子量并分别用DSC、TGA对其玻璃化温度和热失重情况进行了研究,发现共聚物具有良好的热性能。     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Kinetics and Mechanism of Oxidation of Mono- and Polyacetals

Abstract

Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed.     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.     

实施水泵节能技改 实现节能降耗

介绍了内蒙古亿利化学工业有限公司在满足生产的前提下,对现有的循环水泵实施的节能技改及效果。     

泡沫起泡性、稳定性及评价方法

本文论述了泡沫的两个基本性质:起泡性和稳定性。对起泡性和提高泡沫稳定性的方法作了评价。