无卤阻燃ABS/TPU复合材料阻燃性能的研究

采用了微胶囊红磷(MRP)、氢氧化镁(MH)、聚硅氧烷组成复合阻燃剂,对丙烯腈-丁二烯-苯乙烯(ABS)/热塑性聚氨酯(TPU)合金进行改性,获得了环保型阻燃ABS/TPU复合材料。对该复合材料进行了阻燃性能、热稳定性测试和炭层形貌分析。结果表明,当复合阻燃剂MRP/MH质量比为1/1且添加量为16份时,复合材料的极限氧指数(LOI)为25.7%,垂直燃烧性能通过FV-0级;TPU结构中因含氧,有利于MRP/MH阻燃体系阻燃;添加6份聚硅氧烷,复合材料垂直燃烧级别达到FV-0级,聚硅氧烷燃烧过程中通过改变炭层形貌,提高阻燃性。     

阻燃聚酯/纳米SiO_2复合材料的制备及阻燃性能

采用直接酯化法,使用反应型含磷单体合成阻燃聚酯,在酯化产物中加入改性纳米SiO2制备阻燃聚酯/纳米SiO2复合材料,使用热重(TG)分析、扫描电子显微镜(SEM)、极限氧指数(LOI)测试、X射线能谱(EDS)分析等对复合材料进行分析和研究。LOI测试结果显示,随着磷含量的增加,LOI逐渐上升;当纳米SiO2质量分数大于1.8%时,LOI降低。TG分析结果表明,磷元素的加入促进质量保持率的提高,硅元素的加入提高炭层性能和提高质量保持率。SEM显示,燃烧后的复合材料形成多孔且致密的炭层,抑制热量的传输和扩散。EDS元素分析显示,燃烧后磷、硅元素均匀分布在炭层中,增强炭层性能,从而提高材料的阻燃性能。     

无机填料对PA6/MCA阻燃复合材料性能的影响

研究了不同种类的无机填料(硅灰石、碳酸钙)对尼龙6(PA6)/三聚氰胺氰尿酸盐(MCA)阻燃复合材料性能的影响。阻燃性能测试结果表明,PA6/MCA/硅灰石阻燃复合材料为UL94 V–0级,比PA6/MCA阻燃复合材料(V–2级)有显著提高;然而PA6/MCA/碳酸钙阻燃复合材料的极限氧指数却有所下降。扫描电子显微镜测试分析表明,PA6/MCA/硅灰石阻燃复合材料燃烧后的表面炭层呈连续、致密状;PA6/MCA/碳酸钙阻燃复合材料的表面炭层有很多孔洞,且孔洞直径大。傅立叶变换红外光谱测试结果表明,PA6/MCA/硅灰石阻燃复合材料的表面炭层与Si O2能很好地结合,形成致密的保护层,致使其阻燃性能显著提高。另外,力学性能测试结果表明,硅灰石能够提高PA6/MCA阻燃复合材料的拉伸强度,但降低了缺口冲击强度,而碳酸钙的加入却使得PA6/MCA阻燃复合材料的综合力学性能有所下降。     

水滑石对IFR/HDPE复合材料的协效作用

利用熔融共混法制备了水滑石(LDH/)膨胀型阻燃剂(IFR/)高密度聚乙烯(HDPE)复合材料,并对复合材料的力学性能、阻燃性能、热稳定性能和燃烧炭层结构进行了研究。结果表明:LDH对复合材料具有明显的增强作用,在聚磷酸铵/丙三醇/三聚氰胺/HDPE体系中增强幅度最大;LDH能有效提高复合材料的氧指数,且在丙三醇和季戊四醇阻燃复合体系中能有效抑制熔滴和发烟量;LDH可以促进膨胀阻燃体系形成质密多孔炭层并,提高炭层的强度。     

挤出型无卤阻燃三元乙丙橡胶材料的制备与性能

研究了具有不同粒径、不同表面改性的氢氧化镁及其与磷系阻燃剂的并用物、石蜡油增塑剂等对EPDM力学性能、挤出加工性能和阻燃性能的影响.结果表明:纳米氢氧化镁兼具增强和阻燃特性,但大量添加时材料的硬度很高.通过大量微米氢氧化镁和少量纳米氢氧化镁并用,辅以少量磷系阻燃协效剂和成炭剂,协调阻燃性能和力学性能的要求.通过添加少量马来酸酐接枝三元乙丙橡胶、润滑剂并加入石蜡油,可明显改善EPDM的挤出加工性能,最终制备出一种综合性能较好的挤出型无卤阻燃EPDM材料.     

阻燃三元乙丙橡胶研究进展

综述了近10年国内外三元乙丙橡胶(EPDM)及其复合材料的阻燃研究状况,对卤系、金属氢氧化物型、磷系、硅系、膨胀型等阻燃体系分别进行了列表总结和分类讨论。卤系阻燃体系主要论述了常用的十溴二苯醚和十溴二苯乙烷及其协效阻燃体系;金属氢氧化物体系论述了氢氧化镁和氢氧化铝及其协效体系;磷系阻燃体系论述了微胶囊红磷、聚磷酸铵等;硅系阻燃体系论述了蒙脱土、纳米二氧化硅(SiO2)和有机硅氧烷等;膨胀阻燃体系论述了聚磷酸铵/季戊四醇/三聚氰胺(APP/PER/MEL)等阻燃体系。     

多壁碳纳米管协效复合膨胀阻燃剂阻燃EVA的研究

以乙烯-乙酸乙烯酯共聚物(EVA)为基体树脂,大分子磷氮复合阻燃剂(NPS)为主阻燃剂,以多壁碳纳米管(MWCNTs)为协效剂,制备了低烟无卤阻燃EVA复合材料。采用极限氧指数(LOI)、热重分析(TGA)、扫描电镜(SEM)、力学性能和动态热力学性能(DMA)测试等手段对复合材料进行测定,重点考察了MWCNTs对膨胀阻燃EVA体系的影响,探讨了其作用机理。结果表明:MWCNTs对阻燃EVA体系具有很好的协同效应;MWCNTs的加入提高了膨胀炭层在高温时的热稳定性,增加了高温时的残炭量;MWCNTs可以改善膨胀炭层的形貌,提高炭层的隔热性能;0.5%的MWCNTs与29.5%的NPS复配,试样的LOI达到33.6%,拉伸强度达到12.37 MPa;MWCNTs用量在3%以内时,体系仍能保持较好的电绝缘性。     

无卤阻燃ABS复合材料的制备与阻燃性能研究

采用酚醛树脂、磷酸酯、硼酸锌或聚硅氧烷组成复合阻燃剂,与丙烯腈–丁二烯–苯乙烯(ABS)树脂通过熔融挤出混合制备无卤阻燃ABS复合材料。分别研究磷酸酯、聚硅氧烷、硼酸锌用量对无卤阻燃ABS复合材料阻燃性能的影响,考察了阻燃ABS复合材料的热分解行为,观察了无卤阻燃ABS复合材料燃烧产物表面的炭层形貌。实验结果表明,酚醛树脂/磷酸酯复合成炭阻燃体系能有效提高ABS的阻燃性能;硼酸锌和聚硅氧烷对ABS/酚醛树脂/磷酸酯体系阻燃存在阻燃协同效应,提高成炭量;与聚硅氧烷相比,硼酸锌阻燃协同效果较好。     

Nano-CB改性发泡木塑复合材料性能研究

为提升木塑复合材料(WPC)的功能性,将纳米导电炭黑(Nano-CB)作为抗静电和阻燃填料,通过模压法制备阻燃抗静电型发泡木塑复合材料(FWPC)。探究Nano-CB对FWPC性能的影响,分析其作用机理。结果表明,Nano-CB较佳的加入量为8%,此时,FWPC的静曲强度、弹性模量、拉伸强度和冲击强度分别为33.38,2 739,15.59 MPa和4.49 kJ/m²,表面电阻率和体积电阻率对数值均为8,抗静电性能显著提高,氧指数为21.8%,最大热释放速率和平均热释放速率分别为345.92,143.34 kW/m²,阻燃性能小幅增强。SEM分析表明：未加Nano-CB时,FWPC燃烧后表面炭层较薄,结构蓬松,存在大量的孔洞,加入改性Nano-CB后,FWPC燃烧炭层连续致密,表面未见气孔。     

线型酚醛与微胶囊红磷阻燃ABS的研究

采用线型酚醛(Novolac)与微胶囊红磷(MRP)复配阻燃,制备了无卤阻燃丙烯腈-丁二烯-苯乙烯(ABS)复合材料。研究了Novolac/MRP质量比和用量对阻燃ABS性能的影响。研究结果表明:Novolac/MRP的质量比为3/2,总量为15%(质量分数)时,可以制备极限氧指数(LOI)为26.7%,垂直燃烧(UL94)V-0级的无卤阻燃ABS;Novolac的酚羟基与MRP燃烧产生的聚磷酸在高温下发生的脱水成炭反应减缓了ABS的分解;SEM炭层形貌分析表明:Novolac/MRP复合阻燃ABS材料燃烧表面形成了平整、致密的炭层,该炭层能够有效地隔绝燃烧过程所产生的易燃气体及热量,起到较好的阻燃效果。     

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.     

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.     

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.