聚硅氧烷-聚酰亚胺复合材料抗原子氧侵蚀机理分子动力学研究

为了探究不同取代基聚硅氧烷提升聚酰亚胺在太空环境中抵抗原子氧(AO)侵蚀能力的作用机制,本研究采用反应分子动力学(MD)模拟,分析了取代基分别为三氟甲基(-CF_(3))和甲基(-CH_(3))的多面体笼型聚硅氧烷(POSS)复合聚酰亚胺纳米材料的抗原子氧侵蚀性能。结果表明:PI/CH_(3)-POSS和PI/CF_(3)-POSS复合材料均表现出较强的抗AO侵蚀能力,其作用机制是通过形成SiO_(2)层以阻止AO向聚合物基体的传播和热量的传递,其中PI/CF_(3)-POSS复合材料的效果最优,经35 ps的AO侵蚀模拟后其归一化质量为0.83,而PI/CH_(3)-POSS复合材料的归一化质量为0.78。

含氟阻燃透明聚碳酸酯材料的制备及性能

为了获得具有良好阻燃性、透明性及热老化稳定性的聚碳酸酯(PC)材料,将聚四氟乙烯(PTFE)和八苯基倍半硅氧烷(OPS)分别加入含全氟丁基磺酸钾(PPFBS)的PC中制备了含氟阻燃透明PC复合材料,研究了PTFE/PPFBS和OPS/PPFBS对PC阻燃和物理力学性能的影响规律及量效关系,探究了热老化处理对PC复合材料阻燃性能的影响。结果表明,PTFE和OPS的引入提高了PC材料的阻燃性能,添加质量分数0.1%PTFE和OPS的PC复合材料均可在垂直燃烧测试中达到UL 94 V-0级,添加质量分数0.2%的PTFE和OPS后,PC复合材料的极限氧指数分别达到了40.6%和42.2%。与PTFE相比,添加OPS的PC复合材料表现出更好的透明性。PTFE和OPS的引入对PC复合材料拉伸强度的影响较小;当PTFE和OPS质量分数分别为0.2%和0.1%时,PC复合材料可以保持较好的韧性。热老化处理后添加PTFE和OPS的PC复合材料在垂直燃烧测试中均可达到UL 94 V-0级;热老化处理后的锥形量热法测试结果表明OPS与PPFBS可以更好地发挥协同阻燃作用,有效抑制PC材料的热释放,提高残炭率。具有优异阻燃性和热老化稳定性的含氟透明PC复合材料在高端制造业领域具有广阔的应用前景。

左旋氨氯地平分子印迹聚合物的合成及性能研究

采用烯丙基DESs和有机-无机杂化纳米材料POSS作为功能单体,利用两者的协同作用成功制备了氨氯地平分子印迹聚合物。通过优化DESs和POSS的比例,对S-AML的吸附量达到12.8μg/mg,以及印迹因子为6.95。并分别使用Langmuir模型和Freundlich模型对吸附等温线进行拟合,发现MIP的吸附过程更符合Langmuir模型。评价了MIP对血浆加标样品的固相萃取性能,对S-AML的最高回收率可达92.9%。实验结果表明,DESs和POSS的联合使用提高了印迹聚合物对S-AML的选择性和吸附性能。

本征抗原子氧聚酰亚胺超细纤维膜的制备与性能研究

为应对空间探索活动对本征抗原子氧聚酰亚胺超细纤维膜的需求,文章将Si元素与P元素引入到聚酰亚胺分子结构中,采用静电纺丝技术制备了本征抗原子氧聚酰亚胺超细纤维膜。系统研究了Si元素与P元素的引入对超细纤维的化学结构、微观形貌、光学性能、热性能以及抗原子氧侵蚀性能的影响。结果表明:分子结构中引入Si元素和P元素的聚酰亚胺超细纤维膜表面光滑,微观结构呈现连续的纤维状;玻璃化转变温度(T_(g))大于290℃,450℃以下时均表现出良好的热稳定性;且由于引入了Si元素和P元素,在经积分通量为2.0×10^(21) atom/cm^(2)的原子氧辐照后,聚酰亚胺超细纤维膜的原子氧侵蚀速率与Kapton®相比降低了1个数量级。

梯形倍半硅氧烷/海泡石/PC/ABS复合材料的制备与性能

利用双螺杆挤出机通过熔融共混制备无卤阻燃聚碳酸酯/丙烯腈-丁二烯-苯乙烯塑料(PC/ABS)复合材料,分析梯形倍半硅氧烷(TSQ)和海泡石(SEP)对复合材料阻燃性能、热失重和力学性能的影响,结果表明,TSQ可以提高PC/ABS的阻燃性能、热稳定性和低温韧性,在PC/ABS中加入质量分数1%的TSQ,复合材料的阻燃等级达到UL 94 V-0级(3.0 mm)和UL 94 V-1级(2.0 mm),极限氧指数(LOI)达到29.1%,热释放速率峰值(PHRR)、总热释放量(THR)和总烟释放量(TSR)相对PC/ABS分别降低27.4%,21.0%和12.4%,点燃时间(TTI)、火灾性能指数(FPI)和-40℃缺口冲击强度分别提高5.8%,45.5%和51.8%,失重速率最大时温度(Tmax)和750℃残炭率(CRC)分别提高5.2℃和3.0%;在添加了质量分数1%TSQ的PC/ABS中加入SEP,随着SEP添加量的增大,复合材料的初始失重温度(T5%)、Tmax和刚性逐渐增大,韧性逐渐降低,强度和阻燃性能先上升后下降,当SEP的质量分数为4%时,复合材料的阻燃达到UL 94 V-0级(1.5 mm),LOI为34.5%,与未加SEP的TSQ/PC/ABS复合材料相比,PHRR,THR和TSR分别降低17.1%,22.1%和16.3%,TTI和FPI分别提高5.5%和25.0%,Tmax和CRC分别提高8.5℃和6.7%。

苯基乙烯基低聚硅倍半氧烷的合成及乙烯基酯树脂复合物的性能

以苯基三甲氧基硅烷和甲基丙烯酰氧基丙基三甲氧基硅烷为原料,制备了苯基乙烯基低聚硅倍半氧烷(MPOSS),采用^(1)H-NMR,^(13)C-NMR,^(29)Si-NMR和MALDI-TOF-MS证明MPOSS段主体为完整的T10和T12笼型结构。将MPOSS用于乙烯基酯树脂(VER)制备了VER/MPOSS复合物,热重分析、差示扫描量热分析和力学性能测试表明,VER/MPOSS复合物的热稳定性和玻璃化转变温度随MPOSS比例增加而升高;相对于纯VER,添加20%的MPOSS后复合物的弯曲强度、弯曲模量和断裂力分别提高了203%,365%和200%,力学性能显著提升。极限氧指数、锥形量热、热重-红外等阻燃性能与机理研究表明,MPOSS促进了致密炭层的形成,阻止了有机挥发性产物的释放,降低了VER的热释放、烟释放和有毒气体释放量,增强了VER/MPOSS复合物的阻燃性能。综合认为,MPOSS同时提高了乙烯基酯树脂的力学性能、阻燃性能和综合性能。

多阻燃剂协同实现PP泡沫的高效阻燃改性

为提高聚丙烯(PP)泡沫的阻燃性能,以偶氮二甲酰胺(AC)为发泡剂,聚磷酸铵(APP)、双季戊四醇(PER)、三嗪大分子成炭剂(CFA)和有机倍半硅氧烷(POSS)为协同阻燃剂,通过双螺杆挤出造粒和平板硫化仪热压工艺,制备未发泡PP塑料样条以及发泡后的PP泡沫样条。通过对燃烧过程、残炭量与碳层结构分析等方面评估不同配比的PP泡沫复合材料的阻燃性能。结果表明,当AC添加质量分数为2%时,APP催化CFA和POSS来提高PER的炭层质量,形成致密碳层,提高了阻燃性能。当阻燃剂总添加质量分数为30%且APP,PER,CFA和POSS的质量比为15∶5∶8∶2时,PP泡沫复合材料的极限氧指数为32.6%,达到最高阻燃级别HF-1,形成的炭层具有优异的抑烟、隔热效果。

电子束光刻HSQ显影对比度中的图形密度效应

氢倍半氧硅烷(HSQ)是一种高分辨的电子束抗蚀剂,其稀疏结构的分辨率已证实达到亚5 nm。但在实际应用中,很难达到约10 nm周期的密集结构,其中间隙残胶问题是无法实现更高分辨率的根本原因。利用传统大块薄膜获取的显影对比度进行理论计算,得到的结果与实际曝光的分辨率极限存在较大差异。针对这一问题,提出了与图形相关的显影对比度,提高了传统显影对比度在密集图形分辨率极限预测中的适用性。对HSQ的微观显影机理进行了阐述,分析了大块薄膜、亚10 nm周期密集高分辨结构显影过程和显影对比度曲线差异,预测和实验验证了超稀疏结构的超高显影对比度(线剂量对比度约为114)。该研究为改善HSQ工艺及提升计算光刻模型的精度提供了新的思路。

Synthesis and Characterization of Ferrocenyl Substituted Styryl Octasilsesquioxane

4-（2-Ferrocenylethenyl）-phenyl-POSS Fc-CH=CH-C6H6-（C5H9）7Si8O12 （FEPS, Fc： ferrocene）, containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemical structure of FEPS was characterized by FTIR, ^1H-, ^13C and ^29Si- NMR.

Synthesis and Luminescent Property of Polycarbazole/Polyhedral Oligomeric Silsesquioxane Nanocomposites

Polyvinylcarbazole（PVK） composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane（POSS） PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole and were completely dispersed at molecular level in PVK matrix and PVK-POSS nanocomposites display higher glass transition temperature（Tg） in comparison with neat PVK. Optical properties of PVK/POSS nanocomposites were investigated by UV-spectrum and PL-spectrum and the results show that the PVK-POSS nanoparticles have a good interface effect and improve color purity effectively. The maximum absorption wavelength bathochromically shifts gradually with the increasing of the content of POSS. The luminescent intensity becomes higher and higher with the increase of POSS content, and reaches its maximum luminescent intensity when the POSS content is 3% （mass fraction）, while some POSS-rich nanoparticles are present in matrix when contents of POSS are beyond 5%.

Application of Hydrazine Hydrate in the Synthesis of Octa(aminophenyl)silsesquioxane (OAPS) Poss

Octa(aminophenyl)silsesquioxane (OAPS) was prepared from octaphenyl silsesquioxane (OPS) in two steps, first nitration to obtain Octa(nitrophenyl)silsesquioxane (ONPS) then reduction by using the stable, inexpensive, and readily available hydrazine hydrate as the reducing agent in the presence of Iron(III)Chloride catalyst with a yield of around 87%. Hydrazine is a two-electron reducing agent whereas nitro group is a four-electron reduction process. The activated carbon serves as an adsorbent and electrical conductor enabling the reaction to occur by acting as a mediator between a two-electron reagent and a four-electron process. Adsorption provides a reducing potential and a supply of electrons from many hydrazines making possible the initial four-electron process even though each individual hydrazine is a two-electron donor. The product was characterized by FTIR and 1H NMR. The time period for preparation of ONPS from octaphenyl silsesquioxane was considerably shortened to avoid double nitration of the aromatic rings.

Synthesis of Silsesquioxane Cages from Phenyl-cis-tetrol, 1,3-Divinyltetraethoxydisiloxane and Cyclopentyl Resins

The synthesis of T_8, T_ 10 and T_ 12 silsesquioxane cages from a range of starting materials: phenyl-cis-tetrol, 1,3-divinyltetraethoxydisiloxane and cyclopentyl T resins by using tetra n-butylammonium fluoride(TBAF) as the catalyst is described in this paper. The reaction yields obtained viathe current route are better compared to those viathe literature routes. Some of the cage compounds have been characterized by X-ray crystallography.

Study of Flame Retardation of Polycarbonate Modified by Polyhedral Oligomeric Silsesquioxane and Caged Bicyclic Phosphate

The flame-retarded polycarbonate（PC） has been made with octaphenyl polyhedral silsesquioxane（OPS） and/or caged bicyclic phosphate（Trimer）.Thermal gravimetric analysis（TGA）,Fourier-transform infrared（FTIR）,TGA-FTIR,limiting oxygen index（LOI）,and mechanical tests have been employed to characterize the modified PC.The additives of OPS and Trimer in PC have been proved to be effective flame-retardants because of the synergistic interaction between the elements of P and Si.The role of OPS and Trimer in PC degradation are different：OPS participates in the charring of PC,while Trimer makes PC degrade in advance.In addition,OPS and Trimer induced obvious differences in the mechanical properties of PC.

Synthesis and characterization of poly(methyl methacrylate-co-polyhedral oligomeric silsesquioxane)hybrid nanocomposites

A novel poly（methyl methacrylate-co-polyhedral oligomeric silsesquioxane） hybrid nanocomposite was synthesized by free radical polymerization and characterized by 1H NMR, 29Si NMR, and TGA technologies. Compared with PMMA homopolymer, the nanocomposite has better thermal stability.

Fabrication of Layer-by-layer Films of Polyhedral Oligomeric Silsesquioxanes

Layer-by-layer (LBL) self-assembly method was used to fabricate siliceous ultrathin films by using polyhedral oligomeric silsesquioxanes as building blocks. Ammonium salt of octasilsesquioxane acid (OSi8) and poly(diallyldimethylammonium chloride) (PDDA) were alternately assembled onto CaF2 slide to form nanocomposite multilayers. Linear build-up of the LBL films was confirmed by UV-Vis spectroscopy. IR spectrum suggests existence of OSi8 and PDDA in the LBL films. Atomic force microscopic surface topography of the LBL films indicates the OSi8 covers the entire surface of the topmost layer and shows a granular morphology.

Synthesis and Properties of Organic-Inorganic Hybrid Porous Polymers Obtained with Click Addition Reactions of Thiol-Functionalized Random Type Silsesquioxane by and Diacrylate or Diisocyanate Compounds

Organic-inorganic hybrid network polymers have been synthesized by addition reaction of a thiol-functionalized random type silsesquioxane (SQ109) and alkyl diacrylate or diisocyanate compounds. Thiol-ene reaction of SQ109 and 1,4-butanediol diacrylate (BDA) successfully yield porous polymer in toluene initiated by azobis(isobutyronitrile) (AIBN) at 60°C. Morphology of the porous polymers was composed by connected globules, and the diameter of the globules decreased with increasing in the monomer concentration of the reaction system. By contrast, the reaction with 1,6-hexanediol diacrylate or 1,5-hexadiene yielded homogeneous clear gels. Thermal analyses of SQ109-BDA porous polymers indicated that thermal degradation of ester groups of BDA in the polymer network occurred at around 300°C. The porous polymer was also obtained by the reaction using a photo-initiator (Irugacure184) at room temperature, and showed higher Young’s modulus than the corresponding porous polymer obtained with the reaction with AIBN due to the small size of the globules. Young’s modulus of SQ109-BDA porous polymer increased with increasing in the monomer concentration of the reaction systems. Thiolisocyanate addition reactions between SQ109 and hexamethylene diisocyanate (HDI) or methylenediphenyl 4,4’-diisocyanate (MDI) were investigated to obtain network polymers. The reactions in toluene yielded the corresponding homogeneous clear gels. By contrast the reactions in a mixed solvent of toluene (50 vol.%) and N,N-dimethylformamide (50 vol.%) produced porous polymers. The morphology of the porous polymers was composed by connected globules or aggregated particles. The size of globules and particles in the SQ109-HDI porous polymers was larger than those in the SQ109-MDI porous polymers. Thermal degradation of SQ109-HDI and SQ109-MDI porous polymers started at round 260°C and showed endothermic peak at around 350°C derived from degradation of thio-urethane bond.

汽车抗污染用笼聚倍半硅氧烷改性丙烯酸-聚氨酯清漆的制备及性能

随着汽车工业的高速发展,对其漆膜的性能要求也不断提高,其中抗污染性能是非常重要的方面.该研究使用“巨型”笼聚倍半硅氧烷(polyhedral oligomeric silsesquioxane,POSS),采用自由基聚合法将烯丙基七异丁基-POSS等单体合成POSS改性丙烯酸树脂,得出烯丙基七异丁基POSS最佳含量为5.0 PHR,GPC确认Mn为2626,Mw为3763,PDI为1.438.确定POSS改性丙烯树脂为6%、氨基-POSS为1%为最佳量,制备的POSS改性丙烯酸-聚氨酯2K清漆,接触角达96°,远高于竞品.清漆涂膜表面粗糙度由4 nm提升到12 nm左右,提升幅度约200%.耐污染性能提升了50%以上.制备的清漆涂层具有模拟荷叶表面微纳米结构,明显提升了清漆的抗污染性,同时保持了现有清漆的综合性能.

笼形结构硅倍半氧烷提升聚醚复合推进剂力学和燃烧性能研究

复合推进剂研究者期望寻找能够同时提高复合固体推进剂力学性能、催化燃烧和促进铝燃烧的多功能助剂。笼形硅倍半氧烷(POSS)是一种有机-无机杂化物,本文研究了有机基团为苯基、一硝基苯基、二硝基苯基、氨基苯基的四种POSS以1wt%的含量对端羟基环氧乙烷-四氢呋喃共聚醚(PET)/高氯酸铵/铝粉复合推进剂性能的影响。结果表明:四种POSS化合物,均能够提高推进剂抗拉强度和伸长率,八氨基苯基硅倍半氧烷(OAPS)效果最优;均可提高PET推进剂在3~18MPa的燃速,显著降低10.5~18MPa区间的燃速压强指数(n);均能够抑制PET推进剂中铝颗粒在燃烧过程中的团聚,明显降低凝聚相燃烧产物的尺寸,八(二硝基苯基)硅倍半氧烷(ODNPS)效果最好。

Latest developments in EUV photoresist evaluation capability at Shanghai Synchrotron Radiation Facility

Evaluating the comprehensive characteristics of extreme ultraviolet(EUV)photoresists is crucial for their application in EUV lithography,a key process in modern technology.This paper highlights the capabilities of the Shanghai Synchrotron Radiation Facility(SSRF)08U1B beamline in advancing this field.Specifically,it demonstrates how this beamline can create fringe patterns with a 15-nm half-pitch on a resist using synchrotron-based EUV lithography.This achievement is vital for evaluating EUV photoresists at the advanced 5-nm node.We provide a detailed introduction to the methods and experimental setup used at the SSRF 08U1B beamline to assess an EUV photoresist.A significant part of this research involved the fabrication of high-resolution hydrogen silsesquioxane mask gratings.These gratings,with an aspect ratio of approximately 3,were created using electron beam lithography on an innovative mask framework.This framework was crucial in eliminating the impact of zeroth-order light on interference patterns.The proposed framework propose offers a new approach to mask fabrication,particularly beneficial for achromatic Talbot lithography and multicoherent-beam interference applications.

UV引发硫醇-烯反应制备OLED屏封装用八乙烯基倍半硅氧烷/聚氨酯丙烯酸酯液态光学胶

有机发光器件(OLED)是新一代显示屏,其中用于显示屏组件间粘接的液态光学透明胶(LOCA)是OLED的关键材料之一,高折射率、高导热性及高稳定性的LOCA对OLED性能尤为重要。文中采用八乙烯基倍半硅氧烷(OvPOSS)作为增强填料、三羟甲基丙烷三(3-巯基丙酸酯)(TTMP)作为交联剂,通过简单的UV引发硫醇-烯反应将OvPOSS接枝到具有良好黏附性和光学性能的聚氨酯丙烯酸酯(PUA)树脂中,制备出高透明性高折射率的LOCA。研究表明,制备的LOCA在365 nm UV照射20 s内即可固化,相比商用UV胶几分钟的固化时间,固化速度更快、能耗更低;当OvPOSS的质量分数为7%时,相比纯的PUA,折射率提高到1.525以上,热分解温度(T_(d5%))比纯PUA提高了30℃,玻璃化转变温度提高了5.3℃,导热系数从0.0609 W/(m·K)提高到0.1710 W/(m·K),粘接强度从3.16 MPa提高到3.48 MPa,室温日照1440 h后仍可达到99%以上的可见光透过率,水中浸渍3600 h后吸水率仅为0.52%,低于目前文献中的0.70%(24 h),在光电器件封装中具有较大应用前景。