Tuning of polypropylene wettability by plasma and polyhedral oligomeric silsesquioxane modifications

In this work, we have exposed polypropylene (PP) to plasma treatment and then reactively coated with polyhedral oligomeric silsesquioxane-isothiocyanate (POSS-NCS) in order to modify both of its surface characteristics: chemical composition and roughness. The results of scanning electron microscopy (SEM), atomic force microscopy (AFM), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) showed a strong relation between plasma exposure time and PP roughness, as expected. On the other hand, the POSS-coating promoted the reduction of surface roughness, but induced a substantial increase in the water contact angle (WCA), probably due to the modification of the surface chemical nature. Besides, the surface tuning method discussed here is a fast, industrial-suitable procedure which can be applied to different polymers.     

Preparation and properties of polyhedral oligomeric silsesquioxane/epoxy hybrid resins

Octaaminophenyl polyhedral oligomeric silsesquioxane (OAPS) was synthesized using three‐step method and used to modify o‐cresol‐novolac epoxy resin (ECN) for printed circuit board. The influence of OAPS on the reactivity and the final properties of the hybrid networks were evaluated. The intercrosslinking reaction between ECN and OAPS was confirmed by Fourier transform infrared spectra. The ECN/OAPS hybrids have better impact strength, higher electrical resistivity and thermal stability, lower water absorption than the unmodified ECN. The volume resistivity and surface resistivity of the hybrids increase by an order of magnitude or more compared to the neat epoxy. The thermal stability of the hybrids improves by the incorporation of OAPS; the initial decomposition temperature and char yield show an increasing tendency up to 4 wt% loading of OAPS. The hybrids exhibit higher storage modulus and glass transition temperature (T_g) than the neat epoxy. The T_g of the hybrids greatly improves up to 153.3°C at 3 wt% content, much higher than 119.4°C of the neat epoxy. POLYM. COMPOS., 34:1753–1760, 2013. © 2013 Society of Plastics Engineers     

多面体低聚倍半硅氧烷及多面体低聚倍半硅氧烷-聚合物的研究进展

综述了多面体低聚倍半硅氧烷(POSS)的结构、性质与合成方法,重点介绍了单官能团、双官能团、多官能团3类POSS可以通过共聚、缩聚、接枝、共混等多种方式引进聚合物中,形成真正的有机/无机纳米杂化材料,最后指出了POSS的发展方向.     

笼状硅氧烷/硅橡胶复合材料的非等温结晶性能

采用溶液共混法制备了笼状硅氧烷低聚物(POSS)/硅橡胶复合材料,用差示扫描量热仪在不同降温速率下研究了POSS/硅橡胶复合材料的非等温结晶性能,考察了POSS质量分数分别为5%(试样P5)、10%(试样P10)和30%(试样P30)时对复合材料非等温结晶参数和活化能的影响,并选用Ozawa及Ozawa-Avrami联合法对POSS/硅橡胶的非等温结晶性能进行了分析。结果表明,Ozawa-Avrami联合方法适合描述POSS/硅橡胶的非等温结晶现象;POSS/硅橡胶复合材料成核速率的大小依次为P5、P15和P30,生长速率则相反,而结晶速率大小依次为P30、P5和P15。     

聚丁二烯/烯丙基异丁基多面体低聚倍半硅氧烷纳米杂化材料的形貌及性能

对采用活性负离子聚合法制得的聚丁二烯( PB)/烯丙基异丁基多面体低聚倍半硅氧烷(A - POSS)纳米杂化材料进行硫化,采用X射线衍射仪、扫描电子显微镜、差示扫描量热法、热重分析、动态力学性能分析等手段,研究了A - POSS含量对硫化PB/A -POSS纳米杂化材料的微观形貌、耐热性能和动态力学性能的影响.结果表明...     

笼型倍半硅氧烷改性UPR的固化性能与热性能

采用示差扫描量热仪(DSC),热重分析仪(TGA)及动态力学分析仪(DMA)研究了甲基丙烯酰氧丙基笼型倍半硅氧烷(MAP-POSS)与一缩二乙二醇型UPR、苯乙烯的等温共固化反应及动力学,测试了固化物的热性能和动态力学性能。结果表明,固化过程符合自催化反应机理,当体系中MAP-POSS质量分数为5%时,5%热失重温度和残留量5%时的温度较未加体系分别提高7℃和31℃,玻璃化转变温度降低4.2℃,热降解动力学符合1级反应。     

Dielectric properties and solubility of multilayer hyperbranched polyimide/polyhedral oligomeric silsesquioxane nanocomposites

Multilayer hyperbranched polyimide/polyhedral oligomeric silsesquioxane (POSS) nanocomposites were synthesized by the reaction of a bromide‐hyperbranched polyether/POSS and a main‐chain polyimide containing hydroxyl‐functional groups. The first layer was formed through the direct reactions of the main‐chain hydroxyl groups with monochloroisobutyl polyhedral oligomeric silsesquioxane (POSS–Cl). The second and third layers were prepared by the repeated reactions of bromine ether branches that incorporated POSS–Cl with 3,5‐dihydroxybenzyl alcohol. Regardless of the fixed amount of POSS, the higher layers yielded lower dielectric constants. Even when the amount of the POSS loading was reduced 4‐fold, the third layer still had the lowest dielectric constants. The lowest dielectric constant of 2.54 was found in the third layer of the hyperbranched polyimide/POSS nanocomposite because of the large free volume and loose polyimide structures. The densities of the hyperbranched polyimide/POSS nanocomposite corresponded to the dielectric constants. The lower the density was, the higher the free volume was and the lower the dielectric constant was. The experimental results indicated that the hyperbranched polyimide/POSS nanocomposite exhibited increased solubility in comparison with pure polyimide. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

交联POSS-聚氨酯胶的结构与性能研究

采用含八乙烯基的POSS为原料,与不同的聚氨酯预聚体进行共聚,合成了一系列POSS基高分子胶粘剂材料。通过表面红外(ATR)、广角X射线衍射(WAXD)和动态力学分析(DMTA)等方法表征了杂化胶粘剂的热性能。     

八乙烯基多面体低聚倍半硅氧烷的合成与表征

采用水解缩合法,在浓HCl为催化剂的条件下,以乙烯基三甲氧基硅烷为原料合成了八乙烯基多面体低聚倍半硅氧烷,并对合成产物进行了表征;研究了反应温度、反应物的投料比对产物收率的影响.结果表明,在25 ℃,反应物水解缩合21 d,乙烯基三甲氧硅烷、HCl、CH3OH三者的体积比为9∶ 12∶ 200,乙烯基三甲氧基硅烷、HCl的体积分数分别为3.90%、5.43%时,产物的收率达到最高,为26.3%.     

笼状硅氧烷低聚物/聚合物复合材料的研究进展

介绍了笼状硅氧烷低聚物（POSS）的概念、分类及其合成工艺,综述了POSS／聚合物复合材料的制备方法及其在提高聚合物在热稳定性、阻燃性能、医学性能、光电性能、形状记忆及表面性能等方面的应用。     

Synthesis and properties of hybrid urethane polymers containing polyhedral oligomeric silsesquioxane crosslinker

The synthesis and properties of novel hybrid silsesquioxane‐containing urethane polymers using octakis(hydroxypropyldimethylsiloxy)octasilsesquioxane (OHPOSS) as a crosslinker and a hydroxyl‐terminated polybutadiene were studied. Mixing of the OHPOSS with polyurethane prepolymer and chain extenders in solution was found to be successful when tetrahydrofuran was used as the solvent. Thin films of hybrid polyurethanes were obtained. The hybrid materials were elastomers with improved water and solvent resistivity and good thermal stability. The studied OHPOSS appeared to be an effective crosslinker of polyurethanes suitable for, for example, surface coatings applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2023–2030, 2013     

笼型聚倍半硅氧烷交联聚苯乙烯微球疏水性的研究

采用分散聚合法制备聚苯乙烯微球,以甲基丙烯酸为交联剂、过硫酸铵为引发剂,将聚倍半硅氧烷与聚苯乙烯微球进行交联,并对交联后的聚苯乙烯微球进行红外光谱表征和热重分析。探讨了聚合温度对聚苯乙烯微球粒径的影响,着重分析了影响微球疏水性能的聚乙烯和十二烷基硫酸钠的因素。研究结果表明:聚乙烯对交联微球的浸润接触角以及十二烷基硫酸钠对交联微球的吸湿率影响显著;当w(聚乙烯)=40%(相对聚苯乙烯总质量而言)时,接触角为最大值146°,疏水性能较佳;当w(十二烷基硫酸钠)=1.5%(相对于乳液总质量而言)时,吸湿率较低为7.3%。     

多面体低聚倍半硅氧烷合成的研究进展

介绍了多面体低聚倍半硅氧烷(POSS)的分类、结构和性能,POSS是基于化学键合作用而形成的一种分子水平上的纳米有机/无机杂化体,具有规整的立体结构、纳米尺度、优良的相容性和修饰性,其独特的纳米笼形结构使之成为分子结构设计和材料改性的最佳选择。综述了POSS的合成方法及研究进展,如三官能度硅烷或四官能度硅烷在酸、碱或有机盐催化下通过水解缩合反应合成POSS;以POSS为母体,通过封角闭环法和官能团转化衍生法合成POSS;点击化学法制备POSS等。比较了各种方法的优点和存在的问题,指出目前国内POSS的研究重点是合成带有高活性的POSS单体,改进合成路线及工艺,为其工艺化提供技术支持。     

溶液共混法笼状硅氧烷低聚物/硅橡胶复合材料的分散性

通过溶液共混法制备了笼状硅氧烷低聚物（POSS）／硅橡胶复合材料,用X射线衍射仪和透射电子显微镜研究了该材料的分散状况,考察了POSS质量分数以及烘干温度、溶剂含量对POSS在硅橡胶中分散状况的影响。结果表明,POSS质量分数越低,烘干温度越高,越有利于抑制POSS的结晶．进而有利于制备POSS精细分散的P0ss／硅橡胶复合材料;而溶剂含量越少时,更多的POSS以晶体形式从溶剂中析出,从而使得POSS的结晶程度更显著。     

多面体低聚硅倍半氧烷的研究进展

综述了多面体低聚硅倍半氧烷（POSS）的结构特性和合成方法，重点介绍了同取代基、单官能度、双官能度、多官能度四类POSS的合成方法，比较了各种合成方法的优劣，展望了POKS合成研究的发展方向。     

多面体低聚硅倍半氧烷环氧化物的合成研究

用过氧乙酸氧化三乙烯基POSS(多面体低聚硅倍半氧烷)单体制备了POSS环氧化物,通过核磁共振和傅立叶变换红外光谱分析三乙烯基POSS环氧化前后结构的变化,研究并讨论了H2O2浓度、乙酸含量、反应温度、反应时间对三乙烯基POSS环氧化反应的影响.结果表明三乙烯基POSS环氧化的适宜条件是H2O2浓度50%(质量分数),反应温度70℃,CH3COOH与H2O2摩尔比0.51,反应时间h时.     

Thermal and mechanical properties of polyhedral oligomeric silsesquioxane (POSS)/polycarbonate composites

A series of composite materials were produced incorporating polyhedral oligomeric silsesquioxane (POSS) derivatives into polycarbonate (PC), by melt blending. Significant differences in compatibility were observed depending on the nano-scale filler's specific structure: trisilanol POSS molecules generally provided better compatibility with PC than fully-saturated cage structures, and phenyl-substituted POSS grades were shown to be more compatible with PC than fillers with other functional groups. Trisilanolphenyl-POSS/PC composites possess the best overall performance among the POSS materials tested. The high compatibility between the trisilanolphenyl-POSS and polycarbonate matrix results in generation of transparent samples up to 5 wt% POSS content. Slightly enhanced mechanical properties including tensile and dynamic mechanical modulus are observed with the increase of trisilanolphenyl-POSS loading at the cost of decreasing ductility of the nanocomposites. Importantly, upon orientation of the PC/POSS nanocomposite, crystallization of POSS within the oriented material results—this observation is consistent with a growing number of observations which suggest that ‘bottom-up’ formation of structures incorporating multiple POSS cages result from orientation of these nanocomposites, and that the hybrid organic-inorganic inclusions may be at the heart of observed nano-scale reinforcement.     

Polyimide and polyhedral oligomeric silsesquioxane nanocomposites for low-dielectric applications

A novel polyimide (PI) hybrid nanocomposite containing polyhedral oligomeric silsesquioxane (POSS) with well defined architecture has been prepared by copolymerization of octakis(glycidyldimethylsiloxy)octasilsesquioxane (Epoxy-POSS), 4,4′-oxydianiline diamine (ODA), and 4,4′-carbonyldiphthalic anhydride (BTDA). In these nanocomposite materials, the equivalent ratio of the Epoxy-POSS and ODA are adjustable, and the resultant PI-POSS nanocomposites give variable thermal and mechanical properties. More importantly, we intend to explore the possibility of incorporating POSS moiety through the Epoxy-POSS into the polyimide network to achieve the polyimide hybrid with lower dielectric constant (low-k) and thermal expansion. The lowest dielectric constant achieved of the POSS/PI material (PI-10P) is 2.65 by incorporating 10 wt% Epoxy-POSS (pure PI, k=3.22). In addition, when contents of the POSS in the hybrids are 0, 3, 10 wt% (PI-0P, PI-3P, PI-10P), and the resultant thermal expansion coefficients (TEC) are 66.23, 63.28, and 58.25 ppm/°C, respectively. The reduction in the dielectric constants and the resultant thermal expansion coefficients of the PI-POSS hybrids can be explained in terms of creating silsesquioxane cores of the POSS and the free volume increase by the presence of the POSS-tethers network resulting in a loose PI structure.     

Synthesis of multi-walled carbon nanotube/polyhedral oligomeric silsesquioxane nanohybrid by utilizing click chemistry

A new hybrid material consisting of a polyhedral oligomeric silsesquioxane (POSS) and carbon nanotube (CNT) was synthesized by a simple and versatile approach entailing click coupling between azide moiety-functionalized POSS and alkyne-functionalized multi-walled CNTs. This approach provides a simple and convenient route to efficiently functionalize a wide variety of nanoscale nanostructure materials on the surface of CNTs.