聚环状对苯二甲酸丁二醇酯/碳纳米管复合材料的制备及反应动力学研究

采用原位聚合法制得聚环状对苯二甲酸丁二醇酯/多壁碳纳米管(pCBT/MWCNT)纳米复合材料,研究了复合体系的流变行为。研究结果表明:酸化后的MWCNT变短,分散性能明显变好,在MWCNT酸化时间为3h,用量为0.5%条件下,制得的pCBT/MWCNT纳米复合材料的拉伸强度、拉伸模量和弯曲模量达到最大,分别为57.1MPa、1345.3MPa和2754.7MPa,弯曲强度达到93.3MPa,具有较好的力学性能。     

纳米重晶石对聚对苯二甲酸乙二醇酯力学性能及结晶的影响

通过熔融共混法制备了聚对苯二甲酸乙二醇酯/重晶石纳米复合材料,研究了纳米重晶石用量对聚对苯二甲酸乙二醇酯力学性能和结晶行为的影响。结果表明,纳米重晶石对聚对苯二甲酸乙二醇酯有明显的增强作用,在纳米重晶石用量为3%(质量分数)时,对比纯聚对苯二甲酸乙二醇酯,复合材料拉伸强度提高了9.4%,弯曲强度和弯曲模量分别提高了10.8%和21.9%,聚对苯二甲酸乙二醇酯复合材料弯曲强度最高可提高15.8%。在复合材料中,纳米重晶石起到异相成核的作用,提高了聚对苯二甲酸乙二醇酯的结晶速率和结晶度,减少了聚对苯二甲酸乙二醇酯的晶粒尺寸。     

PET/SiO2纳米复合材料的研究进展

聚对苯二甲酸乙二醇酯(PET)是一种应用广泛的工程塑料,为进一步提升材料性能以拓宽其工程应用领域,采用无机纳米二氧化硅(SiO_2)粒子填充改性已成为最为有效的途径之一。针对PET/SiO_2纳米复合材料,主要从纳米SiO_2表面改性、复合材料制备以及复合材料性能三方面综述其研究进展。在此基础上,对PET/SiO_2纳米复合材料的研究方向进行了展望。     

弹性体修饰纳米SiO2粒子改性PBT

选用乙烯-丙烯酸酯-甲基丙烯酸缩水甘油酯(E-MA-GMA)三元共聚物对纳米SiO₂表面进行修饰包覆改性,考察改性后纳米SiO₂在聚对苯二甲酸丁二醇酯(PBT)基体中的分散情况及对PBT复合材料力学性能的影响。FTIR、TEM、SEM结果表明,E-MA-GMA的环氧基团与纳米SiO₂的—OH 基团发生反应,破坏了SiO₂的链状团聚结构,降低了纳米粒子间氢键等作用力。质量分数为10%～20% E-MA-GMA 改性的纳米SiO₂在PBT基体中的分散性及其与基体的相容性均得到明显改善,从而提高了PBT基复合材料的弯曲和拉伸性能。与纯PBT相比,SiO₂/PBT复合材料的拉伸强度提高了9%,而弯曲强度和模量分别提高了14%和20%。     

石墨烯纳米片改性PBT研究

目的采用石墨烯纳米片对聚对苯二甲酸丁二醇酯(PBT)进行改性,以提高其耐热性能和力学性能。方法采用熔融共混法制备PBT/石墨烯纳米片(MLGN)纳米复合材料,通过DSC、SEM、DMA、耐热性能及力学性能测试,研究石墨烯纳米片对PBT性能的影响。结果石墨烯纳米片具有明显的异相成核效果,显著降低了PBT的结晶活化能,加入质量分数为1%的石墨烯纳米片后,结晶活化能降低了66.2%,加入2%后降低了72.8%;石墨烯纳米片与PBT分子链间具有较强的相互作用,有利于提高PBT的结晶峰值温度、玻璃化转变温度、维卡软化温度和拉伸强度。当MLGN质量分数为2%时,玻璃化转变温度提高了1.7℃,维卡软化温度提高了8.8℃,拉伸强度提高了17%左右。MLGN的质量分数在2%以内对冲击强度没有影响。结论石墨烯纳米片能明显改善PBT的耐热性能和力学性能。     

PLA/PBAT/纳米SiO2复合材料的力学性能、热性能和流变性能研究

以聚乳酸(PLA)为基材,己二酸-对苯二甲酸-丁二醇酯共聚物(PBAT)为增韧剂,纳米SiO_2为增强剂,采用熔融共混法制备了PLA/PBAT/纳米SiO_2复合材料;研究了纳米SiO_2不同含量对复合材料力学性能、热性能和流变性能的影响。研究结果表明:随纳米SiO_2含量的增加,复合材料弯曲强度和拉伸强度均先增大后减小,其中,当纳米SiO_2质量为2份时,其力学性能最优,弯曲强度和拉伸强度分别提高了17.17%和14.67%;随纳米SiO_2含量的增加,复合材料初始分解温度和半寿温度分别升高5~8℃和8~10℃,玻璃化转变温度Tg和熔融温度Tm分别升高1~3℃和3~6℃,复合材料热稳定性提高;在3种不同温度(155,160,165℃)下,添加纳米SiO_2的复合材料剪切黏度比未添加纳米SiO_2的大,且二者剪切黏度之差随温度升高而减小,说明其分子间作用力随温度升高而减弱,复合材料可以在155~165℃下进行加工;复合材料为假塑性流体,且随温度升高流动指数n逐渐增大、稠度系数K逐渐减小,复合材料假塑性减弱,流动性改善。     

玻璃纤维表面纳米SiO_2改性对GF/PCBT复合材料力学性能的影响

为研究玻璃纤维(GF)表面纳米SiO2改性对GF增强树脂基复合材料力学性能的影响,利用真空辅助模压(VAMP)工艺制备了不同含量的纳米SiO2表面改性GF增强聚环状对苯二甲酸丁二醇酯(PCBT)复合材料。分析了GF表面改性对GF/PCBT复合材料力学性能的影响,研究了纤维表面改性对GF/PCBT复合材料抗湿热老化性能的影响规律。纤维拔出试验结果表明:经表面处理的GF/PCBT复合材料的界面剪切强度提高了1.16倍;采用含量为0.5wt%和2wt%(与树脂质量比)的纳米SiO2处理GF表面后,复合材料的三点弯曲强度分别提高1.5倍和1.67倍,弯曲模量分别提高1.03倍和1.17倍。SEM结果显示:当纳米SiO2用量为2wt%时,破坏后的纤维表面被树脂完全覆盖,树脂与纤维粘结良好。在湿热条件下,由于纳米SiO2颗粒的存在,水分子很难通过界面相扩散到改性后的材料内部,其抗湿热性能提高。     

PBS/MMT纳米复合材料的制备及表征

以聚丁二酸丁二醇酯(PBS)为基材,经十六烷基三甲基溴化铵(CTAB)改性过的纳米蒙脱土为填料,采用熔融共混法,制备了PBS/MMT纳米复合材料,并研究了该复合材料的热稳定性能、力学性能和流变性能等。结果表明:当改性nano-MMT的添加质量分数为5%时,复合材料的熔点约提高了2.55℃,热初始分解温度提高了33℃;当其添加质量分数为3%时,复合材料的拉伸强度提高了9%,断裂伸长率提高了3%,冲击强度提高了23%;复合材料的流变性能比纯PBS的流变性能有一定程度的提高。     

纳米改性氢氧化铝与包覆红磷协效阻燃PBT的研究

以纳米改性氢氧化铝(CG-ATH)与包覆红磷(RP)为无卤阻燃剂,研究其对聚对苯二甲酸丁二醇酯(PBT)的阻燃性能和力学性能的影响。首先探讨了包覆红磷的添加量对PBT阻燃性能和力学性能的影响,然后固定包覆红磷用量,考察纳米CG-ATH的添加量对PBT/RP复合体系的阻燃性能和力学性能的影响。实验结果表明,纳米CG-ATH和包覆红磷能协效阻燃PBT复合体系,在包覆红磷添加量为10phr,纳米CG-ATH为20 phr时,PBT复合材料的氧指数从21%提高到30%,达到V-0级;复合材料的拉伸强度为57.0 M Pa,冲击强度为3.03 kJ/m2,断裂伸长率为5.79%,表明该PBT复合体系具有优良的阻燃性能和力学性能。     

高韧性PET/PBT合金的制备及性能

甲基丙烯酸环氧丙酯接枝乙烯-辛烯共聚物(POE-g-GMA)用于聚对苯二甲酸乙二醇酯(PET)/聚对苯二甲酸丁二醇酯(PBT)共混物的增韧改性,同时考察了PET、PBT组成变化对共混体系性能的影响。结果表明,加入15%~20%(质量分数,下同)的POE-g-GMA共混体系发生脆韧转变,冲击强度最高可达890 J/m,实现超韧;基体的剪切屈服和橡胶粒子的空洞化是增韧PET/PBT共混物主要形变机理。     

Preparation and characterization of in situ polymerized cyclic butylene terephthalate/graphene nanocomposites

Graphene-reinforced cyclic butylene terephthalate (CBT) matrix nanocomposites were prepared and characterized by mechanical and thermal methods. These nanocomposites containing different amounts of graphene (up to 5 wt%) were prepared by melt mixing with CBT that was polymerized in situ during a subsequent hot pressing. The nanocomposites and the neat polymerized CBT (pCBT) as reference material were subjected to differential scanning calorimetry, dynamical mechanical analysis, thermogravimetrical analysis, and heat conductivity measurements. The dispersion of the grapheme nanoplatelets was characterized by transmission electron microscopy. It was established that the partly exfoliated graphene worked as nucleating agent for crystallization, acted as very efficient reinforcing agent (the storage modulus at room temperature was increased by 39 and 89 % by incorporating 1- and 5-wt% graphene, respectively). Graphene incorporation markedly enhanced the heat conductivity but did not influence the TGA behavior, except the ash content, due to the not proper exfoliation except the ash content.     

低填充SiO_2/聚丙烯纳米复合材料的拉伸特性

通过对纳米 Si O2 辐照接枝聚合改性 ,结合熔融共混工艺制备了低填充 Si O2 / PP纳米复合材料。发现在一定拉伸速度和粒子含量下 ,经辐照改性的 Si O2 / PP纳米复合材料韧性得到显著提高 ,同时强度也有所增加。随拉伸速度的升高 ,纳米复合材料的模量和强度逐渐增大 ,而韧性则随之下降。断面扫描电镜观察表明 ,改性纳米粒子填充复合材料韧性提高的机理以空化和基体大面积剪切屈服为主     

低填充SiO2/聚丙烯纳米复合材料的拉伸特性

通过对纳米SiO2辐照接枝聚合改性,结合熔融共混工艺制备了低填充SiO2/PP纳米复合材料,发现在一定拉伸速度和粒子含量下,经辐照改性的SiO2/PP纳米复合韧性得到显著提高,同时强度也有所增加,随拉伸速度的升高,纳米复合材料的模量和强度逐渐增大,而韧性则随之下降,断面扫描电镜观察表明,改性纳米粒子填充复合材料韧性提高的机理以空化和基体大面积剪切屈服为主。     

Microemulsion processing of silica-polymer nanocomposites

Silica-polymer nanocomposites have been synthesized via polymerizable bicontinuous microemulsions to disperse functionalized/nonfunctionalized SiO2 nanoparticles uniformly in a polymerized microemulsion system as revealed by transmission electron microscopy. The effect of both types of SiO2 nanoparticles in the polymerized microemulsion increased its glass transition temperature (Tg) from 90 to 128 degrees C. TgS of functionalized silica nanocomposites were about 15 degrees C higher than those of nonfunctionalized samples. As expected, both hardness and modulus of the nanocomposites increased with the loading of both types of silica from 2 to 6 wt%. In the case of nonfunctionalized silica, the improvement of properties may be simply exerted by the conventional filler effect due to the better dispersion of nanoparticles of silica in fluid microemulsion prior to the polymerization. The additional effect for the functionalized silica containing a terminal vinyl group is that It could be grafted to the polymer matrix through cross-polymerization with microemulsion-formed polymer to establish strong nanocomposite networks.     

Electrical, thermal, and mechanical properties of polyarylene ether nitriles/graphite nanosheets nanocomposites prepared by masterbatch route

Graphite nanosheets (GN) reinforced polyarylene ether nitriles (PEN) nanocomposites were successfully fabricated through masterbatch route and investigated for morphological, thermal electrical, mechanical, and rheological properties. The SEM images showed that GN were well coated by phthalonitrile prepolymer (PNP) and dispersed in the PEN matrix. Thermal degradation and heat distortion temperature of PEN/GN nanocomposites increased substantially with the increment of GN content up to 10 wt%. Electrical conductivity of the polymer was dramatically enhanced at low loading level of GN; the electrical percolation of was around 5 wt% of GN. The mechanical properties of the nanocomposites were also investigated and showed significant increase with GN loading. For 10 wt% of GN-reinforced PEN composite, the tensile strength increased by about 18%, the tensile modulus increased by about 30%, the flexural strength increased by about 25%, and the flexural modulus increased by 90%. Rheological properties of the PEN/GN nanocomposites also showed a sudden change with the GN loading content; the percolation threshold was in the range of 3–4 wt% of GN.     

Damage tolerance behaviour of cloisite 15A incorporated recycled polypropylene nanocomposites and bionanocomposites

In the present investigation, recycled polypropylene (rPP) used as a matrix was modified by incorporating nanofillers through melt blending technique to prepare a masterbatch of nanocomposites. Untreated sisal fibre and mercerised sisal fibres were further incorporated into the nanocomposites for the preparation of bionanocomposites. Bionanocomposites containing 40 wt% of UT fibre and 5 wt% of MA-g-PP revealed an increase in the tensile strength and modulus to the tune of 27% and 370%, respectively, compared to rPP. The flexural strength and modulus also increased to the tune of 129% and 269%, respectively, compared to rPP. Further, the surface treatment of the fibre slightly increased the mechanical properties and stiffness of bionanocomposites. Interfacial strength between fibre and matrix was also evaluated by using Turcsanyi and Sato–Furukawa models. Damage tolerance of rPP nanocomposites and its bionanocomposites was evaluated using single-edge-notch specimens. The notch length ‘a’ to width ‘W’ ratios, a/W, were chosen as 0.3, 0.45 and 0.6. The nanocomposites showed better damage tolerance as compared to the rPP matrix. The corrugated structure with increased fractured surface area was observed in scanning electron microscopy. Better dispersion of clay in the nanocomposites was observed in transmission electron microscopy.     

硅烷偶联剂在PPy/SiO2纳米导电复合材料制备中的应用

描述了一种合成PPy／SiO2纳米复合材料的新方法。首先用不同百分含量的氨丙基三乙氧基硅烷(APS)处理SiO2,然后通过化学氧化聚合法合成PPy／APS—SiO2纳米复合材料。文中讨论了偶联剂的使用对复合材料的影响及其作用机理。结果表明,用APS处理过的SiO2合成的复合材料其PPy含量、电导率和稳定性都有很大提高,其中用1％APS—SiO2合成的复合材料电导率最高,为38．4S／cm。文中还阐述了偶联剂的预处理对PPy／SiO2纳米复合材料形貌的影响。     

Effect of nanoclays on physico-mechanical properties and adhesion of polyester-based polyurethane nanocomposites: structure–property correlations

Polyester–polyurethane nanocomposites based on unmodified and modified montmorillonite clays were compared in terms of their morphology, mechanical, thermal, and adhesive properties. Excellent dispersion of the modified nanoclay in polymer with 3 wt% loading was confirmed from X-ray diffraction, and low-, and high-magnification transmission electron micrographs. The properties of the clay-reinforced polyurethane nanocomposites were a function of nature and the content of clay in the matrix. The nanocomposite containing 3 wt% modified clay exhibits excellent improvement in tensile strength (by ~100%), thermal stability (20 °C higher), storage modulus at 25 °C (by ~135%), and adhesive properties (by ~300%) over the pristine polyurethane.     

PBS/SiO2纳米复合材料的制备及其结构与性能分析

以聚丁二醇丁二酸酯（PBS）为基材,经-甲基丙烯酰氧基丙基三甲氧基硅烷偶联剂（KH570）改性过的纳米SiO2和未改性的SiO2为填料,采用熔融共混法制备了PBS/SiO2纳米复合材料。研究了所得纳米复合材料的热稳定性能、力学性能和降解性能等。结果表明：当经KH570表面改性的纳米SiO2（KH570与纳米SiO2的质量之比为1：5）的添加质量分数为4%时,复合材料的维卡软化点约提高了10℃,拉伸强度约提高30%,同时复合材料的降解性能比PBS纯料的降解性能有一定的提高。     

Influence of nanotube content on the mechanical and thermo-mechanical behaviour of –COOH functionalized MWNTs/epoxy composites

Functionalized multi-wall carbon nanotubes (MWNTs) with carboxylic acid group (–COOH) have been utilized for the preparation of epoxy nanocomposites. Composites were synthesized using three different wt% (0.5, 0.75 and 1) of MWNTs via the solution mixing technique followed by ultrasonication. Mechanical and thermo-mechanical properties of the fabricated composites have been experimented for the suitability of this material in a variety of structural applications. The flexural modulus, strength, hardness, impact strength and storage modulus increased upon increasing MWNTs contents. Best results have been observed in nanocomposites with 0.75 wt% nanotubes loading, which showed 101, 166 and 61% enhancement in the flexural modulus, hardness and storage modulus, respectively, compared to neat epoxy. Achievement of uniform dispersion and hence formation of improved interface between nanotubes and epoxy was the reason behind the maximum enhancement at this wt%, which is further evidenced by the fracture surface morphology obtained from microscopical investigations.