萘酚对环保型酚醛树脂的改性研究

对萘酚改性环保型酚醛树脂(PF)进行了研究,通过差示扫描量热(DSC)、热重分析(TGA)仪和扫描电子显微镜(SEM)等对改性前后PF的耐磨、耐热性能及力学性能进行了对比.结果表明,改性后的PF耐磨性、耐热性和力学性能均比未改性时有很大程度的提高.萘酚改性的PF可将树脂的质量磨损损失降低54.9%,质量磨损损失率降低56.0%.改性PF的初始失重温度提高70～80℃,可将树脂在600℃时的残余量提高37%.改性后PF的拉伸强度、弯曲强度和冲击强度分别比未改性时提高了519.7、360.4 MPa和43.2 kJ/m~2.     

N-(4-羟基苯基)马来酰亚胺改性酚醛树脂的制备与表征

采用N-(4-羟基苯基)马来酰亚胺(4-HPM)改性酚醛树脂(PF),改性后PF的耐热性能明显优于传统的热塑性PF。质量分数2%的4-HPM改性PF的热分解温度比纯PF提高104.6℃,冲击强度提高130%。改性PF的固化过程分为两个固化阶段:第一阶段是少量羟甲基的缩合;第二阶段为马来酰亚胺的双键打开进行自交联。     

纳米坡缕石/桐油酚醛的原位聚合及其表征

以原位法制备了坡缕石／桐油酚醛树脂。采用热分析系统，对坡缕石／桐油酚醛进行了DSC／TG研究，展示了其热解动态。结果表明：坡缕石／桐油酚醛树脂的耐热性均显著优于普通的酚醛树脂，其初始热分解温度为410℃，当热分解温度≥800℃时，残炭率≥46％。TEM表明：通过超声波分散和硅烷偶联剂处理，纳米坡缕石粉体在复合材料中分散均匀。     

聚磷酸铵改性酚醛泡沫阻燃及耐热性能研究

以苯酚与甲醛为原料合成酚醛树脂,并添加助剂与聚磷酸铵(APP),采用低温模塑发泡法制备改性酚醛泡沫(PF)。采用锥形量热仪、烟密度和热重分析分析不同APP添加量对PF燃烧性能和热稳定性的影响。结果表明：在PF中添加APP可以提高其阻燃性能和耐热性能,在60 kW/m²热辐射强度下热释放速率峰值(PHRR)和总热释放量(THR)随着APP添加比例的提高而降低。当APP添加量为20%时,改性PF的PHRR由90.44 kW/m²下降至11.92 kW/m²。在无焰和有焰两种条件下,改性PF的烟密度随APP添加量增大而提高,透光率降低。升温速率为5℃/min条件下,随着APP添加量的增大,改性PF的热解温度逐渐提高,但APP添加量较低(≤5%)时,不同升温速率下改性PF热解特性均与纯PF无明显差异。升温速率≥30℃/min时,APP与PF热解产物形成的残炭在800℃未发生热解。APP添加量为10%～15%时,改性PF具有良好的阻燃性能和耐火性能。     

桐油改性酚醛树脂的制备及其性能

利用桐油改性酚醛树脂(PF),综合热分析表明改性PF在100～320℃间失重6.30%,320～600℃间失重62.42%,普通PF分别失重16.34%和74.31%,桐油改性PF热稳定性得到了很大提高,但耐热性能未有明显改善。FIIR分析表明桐油成为聚合物结构的一部分;力学测试结果表明桐油改性较大程度改善了PF的韧性。     

阴-阳离子有机坡缕石对对苯二酚的吸附行为

采用微波辅助法制备了一系列阴-阳离子表面活性剂改性坡缕石,研究了改性坡缕石对水中对苯二酚的吸附.结果表明,经阴-阳离子表面活性剂改性后的坡缕石对对苯二酚的吸附能力远大于坡缕石原土及阳离子表面活性剂改性的坡缕石.改性坡缕石对对苯二酚的最大吸附量为137.5 mg/g.等温吸附过程可以用Langmuir方程进行较好拟合,热力学函数计算表明,吸附剂对对苯二酚的吸附是自发的放热过程,吸附热和熵变分别为-93.582 kJ/mol和-299.32 J/mol·K,吸附自由能随温度的升高而增加.     

改性热塑性酚醛树脂的制备及残炭率的影响因素

在苯酚和甲醛原料中加入一定量的SiO2粉体改性剂,可成功制备出改性热塑性PF(酚醛树脂)。以热塑性PF的残炭率为考核指标,采用单因素试验法优选出制备硅改性PF的最优方案。结果表明,当m(苯酚)∶m(甲醛)=(1.30～1.36)∶1时,硅改性PF的残炭率较高且变化不大;当w(SiO2粉体)=0.9%、反应温度为90℃和反应时间为3 h时,改性热塑性PF的残炭率相对较高;此时,Si元素已均匀分布在PF基体树脂上,掺杂的SiO2有助于提高热塑性PF的耐热性能。     

蔗糖八乙酸酯改性酚醛树脂的研究

首次将蔗糖八乙酸酯(SOA)引入到酚醛树脂(PF)体系中,并采用傅里叶红外光谱(FT-IR)、差示扫描量热法(DSC)、热重分析(TGA)和扫描电镜(SEM)等对改性PF的性能进行了表征。结果表明:当w(SOA)≤9.1%时,PF的热分解温度和800℃时的残炭率都有所提高;加入SOA后,PF的固化温度提高,并且由一步固化转变为二步固化;SOA与PF具有良好的相容性,可以有效抑制树脂固化中产生的气泡,有利于降低材料的内部缺陷;当w(SOA)≈7%时,玻璃纤维增强SOA改性PF复合材料的冲击强度提高了9.5%。     

坡缕石型载银抗菌剂的研制

研究了以坡缕石为载体,制备载银抗菌剂的实验工艺以及抗菌剂的主要性能.结果表明,制备坡缕石载银抗菌剂的优化实验参数为温度50℃,时间6h,硝酸银溶液的质量分数为0.1%.     

磷酸盐酸性对酚醛树脂性能的影响

分别用3种酸性不同的磷酸盐,即Ca3(PO4)2,CaHPO4和Ca(H2PO4)2和含六次甲基四胺质量分数4%的B阶酚醛树脂(PF)共混,热压成型制备磷酸盐改性PF,磷酸盐的质量分数均为10%。研究磷酸盐的酸性对PF性能的影响。红外光谱分析表明,CaHPO4和Ca(H2PO4)2与PF反应生成了磷酸酯。热失重分析结果表明,3种磷酸盐均可提高PF的耐热性,Ca(H2PO4)2的提高幅度最大,其改性PF失重5%时的温度比纯PF提高了55℃,CaHPO4次之。冲击强度测试结果表明,CaHPO4和Ca(H2PO4)2改性PF的冲击强度稍有提高,而Ca3(PO4)2改性PF的冲击强度有所降低;3种磷酸盐均能够提高PF的硬度。     

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。     

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.     

责任和责任心的涵义与结构

责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体.     

二甲基二烯丙基氯化铵和丙烯酰胺的合成及应用

用复合引发体系(过硫酸盐-偶氮类引发剂)和脂肪胺类氧化还原体系引发,在实验室获得了单体转化率≥98%,特性粘数高于13.6 dL/g的阳离子共聚物PDA,探讨了控制聚合物分子量的影响因素.     

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.     

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。     

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.     

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.