EPDM/POSS复合材料的阻燃性能

以自行合成的无机-有机杂化材料——笼形八苯基硅倍半氧烷(OPS)与三元乙丙橡胶(EPDM)、硫化剂制成新型复合材料,测定了材料的力学性能和氧指数(LOI)、UL-94阻燃性能,并利用热重分析仪考察了材料的热稳定性,利用锥型量热仪测试了材料的热释放速率等多种燃烧参数。结果表明,OPS复合的EPDM与纯EPDM相比,氧指数有所提高,释热速率降低,热稳定性提高,力学性能得到明显的改善。20份OPS的加入可以使拉伸强度增加一倍,初始热分解温度提高19℃,氧指数提高18.5%,热释放速率降低18.3%。     

笼形八乙烯基硅倍半氧烷／ABS复合材料的热性能和阻燃性

通过螺杆挤出成型法制备了笼形八乙烯基硅倍半氧烷(OVP)/ABS复合材料,采用TGA、氧指数仪和锥形量热仪研究OVP的加入对复合材料热性能和阻燃性能的影响。研究结果表明,在添加引发剂(DCP)的条件下,当乙烯基OVP含量为6.25%时,复合材料的初始分解温度由纯ABS的174℃上升到209℃;氧指数由纯ABS的17.8%上升到的21.4%;热释放速率峰值降为529 kW/m2,比纯ABS降低了近30%。采用SEM对燃烧过后的残炭进行了分析,并探讨了其阻燃机理。     

POSS/聚合物纳米复合材料的制备及其在光电材料中的应用

多面体低聚硅倍半氧烷(POSS)是一种新型有机-无机纳米材料。由于其具有优异的光学、电学、力学和热稳定性能,利用具有笼状结构的POSS带有的一个或多个具有反应活性的官能团进行聚合、接枝、表面改性等将POSS引入聚合物分子链段,制备有机/无机纳米复合材料,可以明显改善聚合物的光、电、热等性能。综述了POSS/聚合物纳米复合材料的制备及其在光电材料中的研究进展。     

环氧树脂/笼型倍半硅氧烷纳米复合材料的阻燃性能与热解机理

探讨了环氧树脂(EP)/笼型倍半硅氧烷(POSS)纳米复合材料的阻燃性能与热降解机理。利用锥形量热计研究了EP以及EP/POSS的燃烧行为,发现POSS可有效降低EP的热释放速率峰值以及总热释放。热失重-红外联用测试结果表明,虽然EP与EP/POSS热裂解产物种类相似,但EP/POSS气相产物均出现在较高温度下,这是由于POSS的存在延迟了EP热解产物的释放,并且在高温下形成了稳定性良好的含硅杂化炭层。此炭层可有效阻止热量与氧传递,从而在燃烧的过程中阻止下部材料进一步燃烧。     

聚硅倍半氧烷改性光固化硅橡胶绝热耐烧蚀材料

以"巯基-双键"交联体系为基础,室温光固化制备了硅橡胶绝热材料,并研究了新型耐烧蚀填料八苯基硅倍半氧烷(OPS)和八乙烯基硅倍半氧烷(OVP)对硅橡胶性能的影响.采用热重分析、力学测试、氧乙炔烧蚀、极限氧指数、锥形量热和扫描电镜对制备的硅橡胶进行了分析.结果表明,OPS和OVP都可以提高硅橡胶的热稳定性和耐烧蚀性,但对...     

POSS/聚丙烯腈星型纳米复合物的制备及热性能

通过自由基聚合的方法,将八乙烯基多面笼形低聚倍半硅氧烷(POSS)与丙烯腈(AN)共聚合得到不同POSS含量的AN与POSS的共聚物(PAN-POSS)。采用傅立叶红外光谱(FT-IR)、硅核磁共振(~(29)Si-NMR)、X射线衍射(XRD)、热失重分析(TGA)和差示扫描量热(DSC)对PAN-POSS共聚物结构和性能进行了表征。研究结果表明,POSS笼形结构以化学键合的方式分子水平上均匀地分散在杂化聚合物中,形成了星型结构POSS/聚丙烯腈纳米复合物,复合物中POSS的含量随着反应单体中POSS配比的增加而增加,复合物的热性能随POSS含量增加明显提高。     

笼型倍半硅氧烷(POSS)/环氧树脂有机无机杂化材料的热性能

为了提高环氧树脂(EP)的性能,采用具有氨基官能团的笼型倍半硅氧烷(POSS)改性.首先通过POSS与EP发生化学反应,形成有机无机杂化树脂;然后固化杂化树脂,得到POSS/EP有机无机杂化材料.文中研究了杂化树脂的凝胶特性和杂化材料的热性能,包括热变性温度(HDT)、玻璃化转变温度(Tg)和高温热分解性能.研究结果表...     

芳炔树脂/POSS固化相容性及热稳定性研究

在聚芳基乙炔树脂(PAA)中分别加入笼型八苯基硅倍半氧烷(OPS)、笼型八氨基苯基硅倍半氧烷(OAPS)和笼型八炔丙基胺苯基硅倍半氧烷(OPAPS)对其进行改性。利用SEM、XRD、红外、DSC和TGA对PAA/POSS体系进行了相容性和热性能的研究。SEM图及XRD结果表明,OPS与PAA相容性差,OAPS次之;由于OPAPS中端炔基可参与PAA的固化反应,因此OPAPS与PAA相容性最好。红外光谱分析结果表明炔基固化反应后主要生成共轭烯和芳环结构,PAA/POSS的复合物中,POSS的笼型结构得以保留。DSC结果表明POSS的加入使得体系放热量有所减少,且OPAPS的加入使体系放热峰向高温区稍有偏移。TGA结果表明OAPS或OPAPS的引入可以基本保持PAA固化产物原有的热稳定性。     

聚氨酯弹性体纳米复合材料的制备与表征

利用几种不同的纳米粒子[包括纳米SiO2、CaCO3、八乙烯基硅倍半氧烷(即八乙烯基POSS)]对聚氨酯弹性体进行改性,制备纳米复合材料。同时,研究了不同纳米粒子对聚氨酯弹性体性能的影响。测试结果表明,聚氨酯弹性体力学性能提高;热失重(TGA)结果表明加入纳米SiO2、CaCO3、八乙烯基POSS后,复合材料的初始热分解温度分别提高了16.01℃、10.95℃、15.00℃,材料热稳定性增强;扫描电镜(SEM)观察到纳米粒子在聚氨酯基体中分散性不够理想,存在团聚现象。     

多官能度氨基苯基笼形硅倍半氧烷的合成表征及在聚碳酸酯中的应用

从合成八苯基硅倍半氧烷(OPS)出发,通过控制硝化条件制备了不同多官能度硝基苯基硅倍半氧烷(NPS),然后对NPS催化还原得到相应的多官能度氨基苯基硅倍半氧烷(APS).利用红外、核磁、元素分析、热失重对多面体低聚硅倍半氧烷(POSS)化学结构和热性能进行了表征.元素分析发现OPS硝化时间越长,硝基越多,但是不是正比关...     

短切聚酰亚胺纤维增强可瓷化三元乙丙橡胶复合材料的制备与性能

以三元乙丙橡胶(EPDM)为基体,高岭土(Kaolin)和滑石粉(Talc)为功能填料,Al(OH)_3为阻燃剂,短切聚酰亚胺纤维(PI Fiber)为增强材料,制备了不同PI纤维含量的可瓷化PI Fiber-Kaolin-Talc-Al(OH)3/EPDM(PKTA/EPDM)复合材料。研究了短切PI纤维对复合材料拉伸性能、热稳定性和微观形貌的影响,分析了短切PI纤维增强复合材料的陶瓷化机制。研究表明,短切PI纤维含量增加会导致可瓷化PKTA/EPDM复合材料拉伸性能下降,当纤维含量与EPDM质量比低于10∶100时,复合材料力学性能良好。可瓷化PKTA/EPDM复合材料在800~1 100℃热解后均发生陶瓷化反应。当PI纤维与EPDM质量比为4∶100~8∶100时,可以有效保持复合材料高温热解后的形状尺寸稳定,并且热解产物弯曲强度在6~18 MPa之间。热分析结果表明,加入PI纤维可以提高可瓷化PKTA/EPDM复合材料的热稳定性。结合热分析和断面SEM分析表明,PI纤维热解、炭化后贯穿在EPDM裂解后的炭层中形成纤维增强炭层结构。这种纤维增强结构在复合材料热解过程中有助于获得尺寸稳定、形状完整的陶瓷产物。     

三元乙丙橡胶/石蜡弹性定形相变材料的制备及性能表征

采用三元乙丙橡胶(EPDM)作为支撑材料,石蜡为相变材料,通过溶液共混法制备了一种弹性定形相变材料(ESSPCMs)。采用扫描电子显微镜、差示扫描量热仪及电子万能试验机研究了EPDM/石蜡不同配比对弹性定形相变材料的断面微观形貌、热学性能和力学性能的影响。实验结果表明,在ESSPCMs中,EPDM和石蜡相容性良好,随着石蜡含量的增加,其相变焓值增大,力学性能提升,渗漏率下降。当石蜡的质量分数为60%时,ESSPCMs的热学和力学性能最优,相变焓值达到148.52J/g,断裂伸长率达到2300%,且经48h冷热循环后渗漏率仅为0.35%。     

Carbon black–clay hybrid nanocomposites based upon EPDM elastomer

The present study explored the effect of nanoclay on the properties of the ethylene–propylene–diene rubber (EPDM)/carbon black (CB) composites. The nanocomposites were prepared with 40 wt% loading of fillers, where the nanoclay percentage was kept constant at 3 wt%. As the modified nanoclay contains the polar groups and the EPDM matrix is nonpolar, a polar rubber oil extended carboxylated styrene butadiene rubber (XSBR), was used during the preparation of nanocomposites to improve the compatibility. Primarily the nanoclay was dispersed in XSBR by solution mixing followed by ultrasonication. After that EPDM-based, CB–clay hybrid nanocomposites, were prepared in a laboratory scale two roll mill. The dispersion of the different nanoclay in the EPDM matrix was observed by wide-angle X-ray diffraction (WAXD) and high resolution transmission electron microscopy. It was found that the mechanical properties of the hybrid nanocomposites were highly influenced by the dispersion and exfoliation of the nanoclays in the EPDM matrix. Thermo gravimetric analysis, scanning electron microscopy and dynamic mechanical thermal analysis was carried out for each nanocomposite. Among all the nanocomposites studied, the thermal and mechanical properties of Cloisite 30B filled EPDM/CB nanocomposite were found to be highest.     

Effect of dynamic crosslinking on crystallization and thermal degradation of polypropylene in polypropylene (PP)/ethylene-propylene DIENE (EPDM) rubber blends

Blends of isotactic polypropylene and ethylene propylene diene (EPDM) rubber were dynamically vulcanized using the dimethylol phenolic resin/stannous chloride crosslinking system. The EPDM blends are thermally more stable than polypropylene (PP). Dynamic curing rendered the vulcanizate thermally more stable than unvulcanized blends. The variations in degree of crosslinking and degree of crystallinity are the main factors for observed increase in thermal stability of vulcanized blends. Degree of crosslinking increases the interfacial adhesion between the PP and EPDM phases. Dimethylol phenolic resin used as a compatibilizer also enhanced the thermal stability of the PP/EPDM blends. Crystallization of PP in the blends of PP/EPDM was also studied through modulated differential scanning calorimetry. Other detailed analyses of endotherm peaks obtained after first and second melts in terms of heat of enthalpy, degree of undercooling, and degree of crystallinity were also evaluated. Kinetic parameters were also determined.     

Development of polyimide–nanosilica filled EPDM based light rocket motor insulator compound: Influence of polyimide–nanosilica loading on thermal,ablation, and mechanical properties

Thermal protection materials are necessary to protect structural components of launch vehicles during lift-off of launching system. The present study deals with the development of a novel thermally protected light rocket motor insulator compound (RMIC) of polyimide–silica filled EPDM nanocomposites. The insulation compound prepared for the studies comprised of aromatic polyimide and nanosilica particles. The addition of these materials in rocket insulator compound enhanced the multifunctional thermal and insulation characteristics. EPDM when grafted with maleic anhydride, contributed polarity in the non-polar EPDM matrix. Nanosilica contributes specifically better erosion resistance. SEM and TEM micrograph of EPDM nanocomposites exhibits good dispersion of nanosilica in polyimide–EPDM matrix. Nanocomposite formation was characterised by FTIR. Density, co-efficient of thermal expansion, thermal conductivity, ablation rate, specific heat, maximum thermal degradation, char yield and mechanical properties of the RMIC have been measured. This developmental study may find wide scope for commercial exploitation.     

Enhancement of ablative and interfacial bonding properties of EPDM composites by incorporating epoxy phenolic resin

Effects of epoxy phenolic resin (EPR) on ablative and interfacial bonding properties of EPDM composites were evaluated. Ablative properties of EPDM composites were enhanced by two folds with incorporating 10 phr EPR. This significant enhancement was attributed to positive effect of EPR on thermal stability and thermal insulating properties of EPDM composites as well as formation of compact char layer onto composites. Furthermore, interfacial shear strength of EPDM composites with carbon fiber/epoxy (CF/EP) composites was increased by 55.6% with incorporating 10 phr EPR, due to interfacial chemical reaction of epoxide groups of EPR molecule from EPDM composites with amine group of hardener from CF/EP composites.     

采用β成核动态硫化PP/EPDM共混物增韧聚丙烯

采用β成核的动态硫化iPP/EPDM共混物即热塑性硫化胶(TPV)改性聚丙烯,并与通用增韧剂聚烯烃弹性体(POE)、三元乙丙橡胶(EPDM)增韧聚丙烯进行比较,考察了增韧体系的力学性能、热性能和相形态.结果表明,随增韧剂含量的增加,增韧体系的拉伸屈服强度和弯曲模量均有所下降,而冲击强度提高.TPV改性体系的强度、模量和...     

溶胶-凝胶法制备含氟聚丙烯酸酯/SiO2杂化材料的结构与性能

用酸催化溶胶-凝胶法制得SiO2溶胶,与丙烯酸酯单体原位聚合,制备了含氟聚丙烯酸酯/SiO2杂化材料。利用红外光谱、场发射扫描电镜、X射线光电子能谱等表征了杂化材料的结构、形态及表面化学组成;研究了SiO2相的形态、分布和界面状况等与杂化材料的表面性能、热学性能和力学性能的关联与影响。结果表明,SiO2在杂化体系中以Si-O网络的形式存在,并与有机相之间有良好键合;杂化材料的疏水性、热稳定性和硬度随着SiO2含量的增加逐渐增强,附着力则先增大后减小。     

In-Situ Chemosynthesis of ZnO Nanoparticles to Endow Wood with Antibacterial and UV-Resistance Properties

Hybrid wood materials have attracted considerable attention because they have combined advantages of both wood and inorganic compounds. This work investigated the microstructural morphology, thermal stability, ultraviolet(UV) stability, and antibacterial property of composites made from wood/ZnO hybrid materials through a facile in-situ chemosynthesis methods. The X-ray diffraction(XRD) and thermogravimetric analysis(TGA) results indicated that the synthesized ZnO particles had an average grain size of about 10.8 nm. The scanning electron microscopy(SEM) observations showed that ZnO nanoflowers self-assembled with nanosheets were presented in wood cell lumens and increased with increasing Zn~(2+)concentrations. ZnO nanoparticles were also generated in the wood cell wall, which was confirmed by the results of energy-dispersive spectroscopy(EDS). The TGA tests also indicated that the thermal stability of wood/ZnO hybrid materials was improved after the formation of ZnO inorganic particles. Finally, the results of antibacterial efficacy tests and UV resistance tests revealed that ZnO nanoparticles showed a promising future as antimicrobial agents against Escherichia coli(E.coli) and UV resistance agents for wood protection.