反应性增容对PP/纳米SiO2性能的影响

研究了反应性增容对聚丙烯(PP)／纳米SiO2复合材料结晶和流变性能的影响。反应性增容使PP的结晶峰温明显提高,结晶速率增大,球晶细化;复合材料的储能模量、损耗模量和复数黏度明显增大,熔体流动速率减小。在环氧功能化纳米SiO2质量分数为3％,反应性增容剂氨基化PP质量分数为10％时,复合材料的结晶峰温从115.8℃升到125．6℃,熔体流动速率从11．0g/10 min降到8．5 g/10 min。     

聚丙烯/粉煤灰微发泡复合材料的制备及发泡性能研究

采用化学微发泡法制备了聚丙烯/粉煤灰(PPFP1919/FA)微发泡复合材料,并对不同FA含量的PPFP1919/FA复合材料的流变性能、发泡质量及力学性能进行研究.结果表明,FA分散在PPFP1919基体中提高了复合材料的熔体强度,使熔体弹性变好,可发泡性提高;FA在发泡过程中还起到了异相成核作用,提供了成核点,从而...     

聚丙烯／弹性体／纳米SiO2复合材料性能研究

以聚丙烯（PP）为基体,以弹性体（POE、TPU）和纳米SiO2为改性剂,采用熔融共混法制备了PP／弹性体／纳米SiO2复合材料,研究了材料的力学性能、动态力学性能、结晶性能与流变性能。结果表明,弹性体和纳米粒子的加入具有明显的协同增韧效应;弹性体和纳米SiO2促进PP的结晶,TPU和纳米SiO2有更好的结晶成核作用;弹性体和纳米粒子使复合材料的模量、复合粘度增大。     

Effect of silane‐grafted polypropylene on the mechanical properties and crystallization behavior of talc/polypropylene composites

Talc‐filled polypropylene (PP) composites coupled with silane‐grafted polypropylene (PP‐g‐Si) were prepared. Effect of PP‐g‐Si on the mechanical properties, crystallization, and melting behavior of PP composites was investigated. Compared with the uncoupled composites, the mechanical properties of Talc/PP composites coupled with a small amount of PP‐g‐Si were increased to some extent. Meanwhile, PP‐g‐Si can promote crystallization rate and increase crystallization temperature of PP in the composites. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2974–2977, 2000     

马来酸酐接枝 SEBS对聚丙烯 / 碳纳米管复合材料性能的影响

采用球磨和熔融共混法，制备了聚丙烯（PP）／碳纳米管（CNT）／马来酸酐接枝SEBS（MA－SEBS）复合材料，结果表明，MA－SEBS促进了CNT在PP基体中的分散，形成完善的逾渗网络，改善了PP／CNT复合材料的抗静电性，提高了CNT对PP的增强作用，对PP／CNT复合材料有明显的增韧作用。     

Crystallization behaviors and foaming properties of diatomite-filled polypropylene composites

The non-isothermal crystallization kinetics and foaming properties of polypropylene (PP) filled with various contents of diatomite were investigated. The results showed that the diatomite had strong effects on the PP crystallization kinetics, which significantly increased the crystallization temperature and reduced crystallite size. These were attributed to the nucleation effect of the diatomite particles and the complex interface properties between the PP chains and diatomite particles. Non-isothermal crystallization can be well described by the Mo’s method. The non-isothermal crystallization activation energy calculated by the Kissinger’s method increased with increased content of diatomite. The foamed PP composites, in particular, the PP composites filled with 10 wt% diatomite had better cell morphology ascribed to the facilitated crystallization and increased polymer melt strength compared with the foamed pure PP.     

Fabrication of surface-treated BN/ETDS composites for enhanced thermal and mechanical properties

The ceramic/polymer composites based on epoxy-terminated dimethylsiloxane (ETDS) and boron nitride (BN) were prepared for use as thermal interface materials (TIMs). 250 µm-sized BN was used as a filler to achieve high-thermal-conductivity composites. To improve the interfacial adhesion between the BN particles and the ETDS matrix, the surface of BN particles were modified with silica via the sol–gel method with tetraethyl orthosilicate (TEOS). The interfacial adhesion properties of the composites were determined by the surface free energy of the particles using a contact angle test. The surface-modified BN/ETDS composites exhibited thermal conductivities ranging from 0.2 W/m K to 3.1 W/m K, exceeding those of raw BN/ETDS composites at the same weight fractions. Agari׳s model was used to analyze the measured thermal conductivity as a function of the SiO₂-BN concentration. Moreover, the storage modulus of the BN/ETDS composites was found to increase with surface modification of the BN particles.     

Effect of silane coupling agents on the properties of pine fibers/polypropylene composites

In the present work, PP‐based composites, reinforced with surface modified pine fibers, have been prepared. The surface of the fibers has been treated with several silane derivatives bearing specific functionalities. ? NH₂, ? SH, long aliphatic chain, and methacrylic group were chosen as functionalities of the silane derivatives for evaluating the compatibility with the polymer matrix. Mechanical analysis, contact angle and XPS spectra, SEM microscopy, and water uptake measurements were used as characterization techniques for evaluating the nature of composites. XPS as well as contact angle measurements demonstrated that pine fibers and silane derivatives were effectively coupled. The mechanical analysis showed an increase in Young's and flexural moduli, by 12% and 130% respectively, and nonsignificant changes in the ultimate tensile strength were noted after surface modification. Water uptake measurements revealed a low water absorption by the materials, always lower than 2 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3706–3717, 2007     

硅烷偶联剂对纳米SiO2／NR复合材料结构与性能的影响

用硅酸钠制备纳米SiO2乳液,用氯化铵控制粒径大小,然后与天然胶乳共混共沉制备出SiO2／NR复合材料。采用SEM对SiO2／NR复合材料断面进行分析,观察SiO2粒子大小和形态,并对其力学性能进行测试。结果表明,经过硅烷偶联剂处理的纳米SiO2在复合材料中分散均匀,力争性能较好。     

挤出循环对聚丙烯/竹粉复合材料力学及发泡性能的影响

通过双螺杆挤出机对30％(质量分数,下同)竹粉增强聚丙烯(PP/BP)复合材料进行循环加工,研究了挤出循环次数对PP/BP复合材料流变性能、力学性能和发泡性能的影响.结果表明,随着挤出循环次数的增加,PP/BP复合材料的表观黏度(η)先升高后降低,力学性能先增强后减弱,经第6次挤出循环后,其η、弹性模量和弯曲模量比1次...     

The preparation and performance analysis of chemical-treated maize straw fibers and Its high-performance polypropylene/chemical-treated maize straw fibers/maleic anhydride grafted polypropylene/silane coupling agent composites

In recent years, there has been an increasing industrial interest in maize straws. In this work, chemical-treated fibers (CTF) were fabricated based on wasted maize straws by chemical treatment combined with stirring. The experimental results suggest that a part of lignin in CTF was removed after chemical treatment, which resulted in the smooth surface morphology, better thermal stability, and even higher degree of crystallinity of CTF. Furthermore, the CTF were used to composite with polypropylene (PP). With the addition of PP-g-MAH and silane coupling agent (SCA), the compatibility between CTF and PP was improved and thus the mechanical performance of PP composites was also improved. At the same time, the tensile strength (54.9 ± 5.4 MPa), Young's modulus (1950 ± 246 MPa), specific strength (49.4 ± 3.9 MPa g⁻¹ cm³) and impact strength (3.6 ± 0.3 kJ/m²) of the PP/CTF/PP-g-MAH/SCA (50/50/6/0.95) composite was increased by about 51%, 177%, 20%, and 113% relative to pure PP, respectively. In conclusion, transforming the wasted maize straws into CTF is an effective way to reduce environmental pollution and meet the growing global demand for energy-saving materials.     

Influence of grafted polypropylene on the mechanical properties of mineral‐filled polypropylene composites

The purpose of this work was to study how mineral fillers would behave in a polypropylene (PP) matrix when PP modified with maleic anhydride (MA) and/or itaconic acid (IA) was used as a coupling agent in the preparation of mineral‐filled PP composites. The composites were characterized with tensile mechanical measurements and morphological analysis. The optimum amount of the coupling agent to be used to obtain composites with improved mechanical properties was established. The results indicated that these coupling agents enhanced the tensile strength of the composites significantly, and the extent of the coupling effect depended on the nature of the interface that formed. The incorporation of coupling agents enhanced the resistance to deformation of the composite. The behavior of IA‐modified PP as a coupling agent was similar to that of a commercial MA‐modified PP for the filled PP composites. Evidence of improved interfacial bonding was revealed by scanning electron microscopy studies, which examined the surfaces of fractured tensile test specimens; their microstructures confirmed the mechanical results with respect to the observed homogeneous or optimized dispersion of the mineral‐filler phase in these composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2343–2350, 2007     

硅烷偶联剂对纳米二氧化硅/硅橡胶复合材料界面作用及性能的影响

利用单官能团偶联剂六甲基二硅氮烷(HMDS)及双官能团偶联剂γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)分别对纳米Si O2进行表面改性,制备了改性Si O2/甲基乙烯基硅橡胶(MVQ)复合材料,研究了2种偶联剂对Si O2的改性效果,表征了改性Si O2在MVQ中的分散状态,且考察了2种偶联剂对复合材料结合胶、动态力学性能、交联密度及拉伸性能的影响。结果表明,HMDS和KH-570都能实现对Si O2改性接枝,且2种改性Si O2具有相同的摩尔接枝率;HMDS改性Si O2分散于基体中,且存在一定量团聚体,而KH-570改性Si O2的分散性较好,部分达到原生粒子级分散,颗粒与基体相容性提高;低应变条件下,Si O2经改性后,复合材料的储能模量(G')和损耗因子(tanδ)下降,且KH-570改性体系的G'低于HMDS改性体系,而tanδ高于HMDS改性体系;在高应变条件下,未改性与改性Si O2/MVQ复合材料的G'趋于一致,而KH-570改性体系的tanδ低于HMDS改性体系;改性Si O2/MVQ复合材料具有更高的交联密度和拉伸性能,且KH-570改性体系的交联密度和拉伸性能均高于HMDS改性体系。     

Effect of strain rate on the tensile properties of mini-SiC/SiC composites

SiC/SiC composites are the ideal candidates for hot-end components in aerospace and other high-tech fields. In recent years, as one type of material with simple structures, mini-composites have been widely used to study or initially verify the properties of ceramic matrix composites (CMC). Nevertheless, attentions were rarely paid on the influence of strain rate on the mechanical properties of mini-composites. In this study, based on mini-SiC/SiC composites, we investigated the effect of the strain rate on their tensile strength, initial tensile modulus, Weibull modulus, and fracture work. Furthermore, the underlying mechanisms were discussed and the exact constitutive model of the as-prepared mini-SiC/SiC composites was constructed according to the Michaelis-Menten and generalized linear models. This work can fill the gaps in the CMC research in some degree and provide a preliminary theoretical basis for the formulation of tensile properties test standards of mini-composites.     

Effect of intercalation agent on the structure and properties of OMMT and RTV/OMMT composites

Novel room‐temperature vulcanized silicone rubber (RTV)/organic montmorillonite (OMMT) composites have been prepared. Di(2‐oxyethyl)‐12 alkane‐3 methyl‐amine chloride and hydrogen silicone oil were used as intercalation agents to treat Na⁺‐montmorillonite and form two kinds of OMMTs. The structure and properties of OMMT were characterized by Fourier transform infrared spectroscopy and X‐ray diffraction (XRD). The intercalation mechanism of different types of intercalation agents was proposed. RTV/OMMT composites were prepared using these OMMTs. Properties such as viscosity, hardness, tensile strength, elongation at break, and thermal stability were researched and compared. A combination of swelling test, XRD and transmission electronic microscopy studies was used to characterize the structure and reinforcing mechanism of these OMMTs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

改性剂对聚丙烯流变性能和发泡行为的影响

在改性聚丙烯PPFP1920中加入丙烯酸类树脂改性剂(记作G200)进行共混改性,制备了PPFP1920/G200复合材料,研究了G200含量对聚丙烯流变性能、发泡行为的影响.结果表明:随着G200含量的增加,复合材料的熔体流动速率大幅降低,复数黏度和低频储能模量提高,低频损耗因子降低,熔体弹性变好,复合材料可发泡性提...     

Effect of fly ash washing conditions on the properties of coupling agent modified polypropylene/fly ash composites

Two fly ash samples (one from UK, UKFA, and another from South Africa, SAFA) were washed with water and 1 M hydrochloric acid (followed by water) prior to incorporation (at 65% wt) into polypropylene homopolymer, containing an unsaturated carboxylic acid coupling agent (Lubrizol Solplus^® C800) with dicumyl peroxide free radical initiator. Melt blending was achieved using a Haake Rheomix 600 mixing chamber, and composite test plaques were compression moulded. Flexural and impact testing was then carried out. Unwashed and water washed fly ash–based composites responded well to C800 modification, and flow microcalorimetry (FMC) and diffuse reflectance Fourier transform infrared spectroscopy studies confirmed strong interaction between C800 and fly ash. However, washing the fly ash with HCl led to a reduction in composite flexural and impact properties. Scanning electron microscopy imaging of the latter composite fracture surfaces revealed poor filler‐matrix adhesion, which was thought to be due to reduced interaction between C800 and HCl washed fly ash. The latter was confirmed using FMC. Reduction of C800/fly ash interaction led to a reduction in the nucleation of polypropylene (PP) crystallization and a decrease in melt flow rate. The latter may be due to a shift in locus of PP–C800 addition reactions from the interfacial region to the bulk matrix. POLYM. COMPOS., 35:698–707, 2014. © 2013 Society of Plastics Engineers     

Production and characterisation of vapour grown carbon fiber/polypropylene composites

Polymeric composites are widely used in the aircraft and automotive industries. Their high strength-to-weight ratio makes significant weight reduction possible. Beside this advantage, the polymer materials also offer a good corrosion resistance but the mechanical and electrical properties are not satisfactory. In order to increase these properties, vapour grown carbon fibers (VGCF) with high strength and metal-like electrical conductivity can be embedded in the polymeric matrix. To ensure a good adhesion between the fibers and the polymer matrix a functionalization of the chemically inert surface of the fibers is necessary.In the present research work oxygen-containing functional groups were introduced on the fiber surface through cold plasma treatment. Measurements of the fiber surface energy after plasma functionalization showed an enhancement of at least 50% of the initial value. The VGCF/PP composites with different amounts of VGCF were made through extrusion and injection molding. The results show that the degree of fiber surface functionalization and the fiber distribution and orientation in the polypropylene (PP) matrix may strongly influence the mechanical properties of the composite.     

柠檬石膏的表面改性对柠檬石膏/聚丙烯复合材料性能的影响

本文研究了单一和混合偶联剂表面改性的柠檬石膏对柠檬石膏/聚丙烯复合材料的力学性能,结晶度,熔点的影响;结果表明:单一偶联剂表面改性的柠檬石膏使柠檬石膏/PP复合材料的拉伸强度,弯曲强度和弯曲模量较PP有不同程度提高,钛酸酯和铝酸酯偶联剂对柠檬石膏的表面改性具有较好效果。混合偶联剂表面改性的柠檬石膏使柠檬石膏/PP复合材料的冲击强度较单一偶联剂表面改性柠檬石膏填充PP的复合材料提高了34.7%,而拉伸强度,弯曲强度和弯曲模量均有一定下降。差示扫描量热(DSC)分析结果显示柠檬石膏的加入可以提高聚丙烯的结晶度,对复合材料的熔点几乎没有影响;柠檬石膏的表面改性对复合材料中PP的结晶度和熔点均没有明显影响。     

Effect of surface treatment on the properties of polypropylene/nanoboehmite composites

Boehmite nanoparticles are surface modified with alkyl phosphorous acid to improve their dispersion in polypropylene. Effective grafting is evidenced by NMR, elemental analysis and by the fact that the dispersion ability (or disagglomeration) of grafted boehmite particle in nonpolar solvent is significantly altered. High dispersibility level in PP is obtained with long alkyl chain surface modifiers. The improvement of the nanocomposites thermal stability is correlated with the nanoparticles dispersion level. However, composite with well dispersed nanoparticle did not demonstrate enhanced mechanical properties because of weak polymer/filler interactions with the PP matrix. Better reinforcement is noticed for polypropylene composite loaded with untreated boehmite or treated with shorter alkyl chain. For these composites, the nanoparticles acted as nucleating agents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010