天然胶乳/有机粘土复合材料的结构和拉伸诱导结晶行为研究

采用乳液法制备天然胶乳/有机粘土纳米复合材料(NRLCNs),研究NRLCNs的结构、试样厚度和有机粘土用量对NRLCNs拉伸诱导结晶行为的影响。结果表明:NRLCNs为插层型结构,NRLCNs的物理性能明显优于NRL胶料;试样厚度相同时,有机粘土用量为3份的NRLCNs物理性能最优;有机粘土用量相同时,试样厚度较小的NRLCNs物理性能较优;随着拉伸强度的增大,NRLCNs的定伸应力逐渐增大,当达到临界应变值时,定伸应力迅速增大,产生拉伸诱导结晶行为,试样厚度较小的NRLCNs易产生拉伸诱导结晶行为。     

氯丁橡胶/有机粘土纳米复合材料的拉伸诱导结晶行为研究

通过熔体插层法制备氯丁橡胶(CR)/有机粘土纳米复合材料(CRCNs),研究有机粘土用量对CRCNs拉伸诱导结晶行为的影响。结果表明:随着应变增大,CRCNs的应力增大,当应变达到一定值时,应力迅速增大,诱导结晶集中产生;随着有机粘土用量增大,CRCNs发生拉伸诱导结晶行为的应变增大;当有机粘土用量为5份时,CRCNs的拉伸性能较好,CRCNs中橡胶分子链成功插层进入有机粘土片层,有效扩大了有机粘土层间距,有机粘土与橡胶基体界面作用较强,在橡胶基体中的分散较均匀。     

有机粘土/异戊橡胶纳米复合材料应变诱导结晶行为的研究

制备有机粘土(OC)/异戊橡胶(IR)纳米复合材料(IRCNs),研究OC用量对IRCNs拉伸性能和应变诱导结晶行为的影响。结果表明:IRCNs中OC的衍射峰角度较OC不同程度减小,且细致、均匀地分散于橡胶基体中,形成有序插层结构;随着OC用量增大,IRCNs的拉伸强度先增大后减小,当OC用量为5份时,IRCNs的拉伸强度最大(16. 44 MPa),较IR提高41%;IRCNs的应变诱导结晶行为随着OC用量增大向低应变转移,应力临界诱变点逐渐减小;当应变小于应力临界诱变点时,IRCNs中OC的取向度较低,当应变大于应力临界诱变点时,OC取向明显并趋于极限。     

顺丁橡胶/有机黏土纳米复合材料的拉伸诱导结晶行为

采用熔体法制备了顺丁橡胶/有机黏土(OC)纳米复合材料(BRCNs),通过偏光显微镜观察BRCNs在不同拉伸情况下的聚集态结构,并研究了OC的结构及用量对顺丁橡胶拉伸诱导结晶行为的影响。结果表明,随着拉伸形变的增加,BRCNs的定伸应力呈增大趋势;当应变达到某一值时,BRCNs的定伸应力迅速增加,拉伸结晶化集中产生;随着OC用量的增加,BRCNs拉伸诱导结晶行为在较低的应变条件下产生。     

聚合物/粘土纳米复合材料的插层/解离和结晶行为研究近展

从聚合物/粘土纳米复合材料的相态结构、影响粘土插层解离和聚合物结晶行为的因素等方面对聚合物/粘土纳米复合材料的研究近况进行了综述。     

氯丁橡胶/有机黏土纳米复合材料应变诱导结晶行为

通过熔体插层法制备氯丁橡胶/有机黏土纳米复合材料(CRCNs),利用偏光显微镜观察CRCNs在不同应变条件下微观结构的变化。主要研究有机黏土对CRCNs应变诱导结晶行为的影响,并通过XRD和SEM表征了CRCNs的微观结构。结果表明: 当有机黏土含量为5 phr时,CRCNs的综合力学性能最优。随着应变的增加,CRCNs的应力也在增加;当应变达到一定值时, CRCNs的应力迅速增加,应变诱导结晶集中产生。随着有机黏土含量的增加, CRCNs拉伸诱导结晶行为在高应变条件下产生。分析原因是氯丁橡胶基体中有机黏土与橡胶分子的插层结构逐渐减少,诱导结晶能力变弱。     

环氧树脂/粘土纳米复合材料研究现状

描述了粘土的结构特征和有机化蒙脱土的制备,介绍了插层复合法的基本原理及其在环氧树脂／粘土纳米复合材料制备中的应用,以及近年来国内外环氧树脂／粘土纳米复合材料的研究现状。     

改性纳米粘土/天然胶乳复合材料的制备与性能研究

研究表面改性剂对纳米粘土/天然胶乳复合材料性能的影响。结果表明:烷基表面活性剂对纳米粘土改性后,天然胶乳硫化胶膜老化前后的拉伸强度均明显提高,十六烷基三甲基溴化铵(CTAB)的改性效果最好,当改性纳米粘土用量为2份时,天然胶乳硫化胶膜的拉伸强度最高;CTAB改性纳米粘土能提高天然配合胶乳的保存稳定性、粘度和机械稳定性,并提高天然胶乳硫化胶膜的物理性能和耐热老化性能,补强效果明显。     

有机粘土/聚烯烃弹性体纳米复合材料的结构与性能

采用熔体插层法制备有机粘土/聚烯烃弹性体(POE)纳米复合材料,研究有机粘土起始片层间距及用量对复合材料结构与性能的影响.结果表明:POE分子链插层进入有机粘土片层之间形成插层结构,并且有机粘土起始层间距越大,所制备纳米复合材料的物理性能越好.随着有机粘土用量的增大,有机粘土/POE纳米复合材料物理性能逐渐提高.     

环氧树脂/粘土纳米复合材料的研究

采用原位插层聚合法制备环氧树脂／粘土纳米复合材料,用X衍射（XRD）,红外光谱（FTIR）,差示扫描量热法（DSC）,扫描电镜（SEM）对有机化蒙脱土（OMMT）和环氧树脂／粘土纳米复合材料进行测试与表征,结果表明,与纯环氧树脂固化物相比,环氧树脂／粘土纳米复合材料的力学,热学性能有较大的改善和提高。     

Nonisothermal Crystallization and Melting Behavior of EVA/OMWNTs Nanocomposites

EVA/OMWNTs nanocomposites have been successfully prepared by a simple melt compounding method. The nonisothermal crystallization behaviors of the EVA/OMWNTs nanocomposites are strongly dependent on the degree of crystallinity (X_c), peak crystallization temperature (T_p), half-time of crystallization (t_1/2), and Avrami exponent (n) on the OMWNTs content and cooling rate. The dependence of the crystallization activity energy on the extent of relative crystallization for the plain EVA and the EVA/OMWNTs nanocomposites shows that ΔE increases with the increase in the relative degree of crystallinity below about 5%, and the ΔE decreased when the relative degree of crystallinity was greater than about 5%.     

Investigation on Unusual Crystallization Behavior in Polyamide 6/Montmorillonite Nanocomposites

The crystallization behavior and crystal structure of polyamide 6/montmorillonite (PA6/MMT) nanocomposites were investigated by differential scanning calorimetry and X‐ray diffraction, and an interesting behavior was observed. The material was prepared via melt compounding using an organophilic clay obtained by co‐intercalation of epoxy resin and quaternary ammonium into Na‐montmorillonite. A maximum in degree of crystallinity was obtained at 5 wt.‐% MMT and the reasons for this, based on the MMT layer distribution, were discussed. The degree of crystallinity showed a strong dependence on the cooling rates. In contrast with typical behavior, a higher cooling rate resulted in a higher degree of crystallinity. In nanocomposites, the γ‐crystalline phase was dominant.     

Investigations of the Non-Isothermal Crystallization Behavior of Polyamide 6/Polyethylene-Octene/Organomontmorillonite Nanocomposites

The crystallization behavior of polyamide 6/polyethylene-octene/organomontmoril- lonite (PA 6/POE/OMMT) nanocomposites fabricated via melting intercalation route was investigated using differential scanning calorimeter (DSC). The crystallization kinetics under non-isothermal conditions was analyzed by Jeziorny method and Mo method, and the crystallization kinetics parameters were obtained. It was found that nano-clay acted as a heterogeneous nucleation agent and the semi-crystallization time was prolonged with the OMMT loading increasing. The activation energy for non-isothermal crystallization of such nanocomposites was calculated according to the Huffman-Lauritzen theory. The average size of the composite nanocrystals was reduced with introduction of OMMT to the synthetic system.     

聚乳酸/聚己内酯/氧化石墨烯纳米复合材料结晶性能与力学性能的研究

利用氧化石墨烯(GO)改性聚己内酯(PCL)与聚乳酸(PLA)共混,制备了PCL/PLA/GO纳米复合材料。采用DSC、XRD和POM测试手段,表征了复合材料的结晶性能,通过SEM扫描观察了纳米复合材料的微观形貌,并对复合材料的力学性能进行了测试。结果表明:随着GO含量的增加,结晶度有一定程度的提高,且晶核密度增加;GO片层穿插在PLA相中,褶皱或重叠,这跟GO的分散均匀性有关,且复合材料的拉伸强度从50.38 MPa升高到55.91 MPa,而断裂伸长率则有一定程度的降低。     

Morphology,Rheological Properties,and Crystallization Behavior of Polypropylene/Clay Nanocomposites

Polypropylene/clay nanocomposites (PP/I.44P, PPCNs) were prepared in a twin-screw extruder using maleic anhydride grafted polypropylene (MAPP) as a compatibilizer. The intercalation of polypropylene into nanoclay particles was studied using X-ray diffraction. Rheological properties of the nanocomposites were investigated using a rheometer. The enhanced complex viscosity at low frequency regime indicated that the melt elasticity and melt strength of the nanocomposites were improved by adding nanoclay. The non-isothermal crystallization behavior of the nanocomposites was studied using differential scanning calorimetry (DSC) at various cooling rates and was analyzed with the Avrami method. It was found that the nanoclay acted as a heterogeneous nucleating agent resulted in higher crystallization temperature and higher crystallization rate than neat PP. Polarized optical microscopy revealed that the spherulites in the nanocomposites were finer than in the neat system.     

熔体法OC/IIR/EPDM纳米复合材料的结构与性能研究

采用机械共混法制备有机粘土(OC)/IIR/EPDM纳米复合材料,并对其结构和性能进行研究.试验结果表明:采用机械共混法制备的OC/IIR/EPDM复合材料为插层型纳米复合材料;IIR与EPDM具有良好的相容性;当OC用量为30份、IIR/EPDM并用比为50/50时,OC/IIR/EPDM纳米复合材料的气密性能和物理性能较好.     

PE/OC纳米复合材料的结晶性能与流变性能

以聚乙烯(PE)为基体,通过熔融插层法将有机黏土(OC)加入到PE基体中,制备了PE/OC纳米复合材料,并对复合材料的微观结构、结晶性能、流变性能以及力学性能进行表征测试.结果表明:w(OC)为3％时,PE/OC纳米复合材料形成了部分剥离型结构,复合材料的结晶度最大,且拉伸强度最大,达27.6?MPa,但随着OC含量进...     

Effect of Nanoparticle Surface Treatment on Nonisothermal Crystallization Behavior of Polypropylene/Calcium Carbonate Nanocomposites

Polypropylene (PP)/CaCO₃ nanocomposites were prepared by melt-blending method using a Haake-90 mixer. The CaCO₃ nanoparticles were surface modified with a coupling agent before compounding. A fine dispersion of the modified nanoparticles in the nanocomposites was observed by transmission electron microscopy (TEM). Effects of surface treatment of CaCO₃ nanoparticles on the nonisothermal crystallization behavior and kinetics of PP/CaCO₃ nanocomposites were investigated by differential scanning calorimetry (DSC). Jeziorny and Mo methods were used to describe the nonisothermal crystallization process. It was shown that the crystallization temperature of the nanocomposites increased due to the heterogeneous nucleation of the surface-treated nanoparticles. It was found that the nanoparticles modified with a proper content range of coupling agent could facilitate the nonisothermal crystallization of the nanocomposites under certain conditions (the cooling rate and the relative degree of crystallinity). This may be a potential application for the crystallization controlling of composites in manufacturing. In addition, the activation energy of crystallization for the nanocomposites and the nucleation activity of the nanoparticle were estimated by using Kissinger and Dobreva's methods, respectively. It could be concluded that the surface-treated nanoparticles had a strong nucleating activity, which caused the decrease of the activation energy of the nanocomposites.