热氧老化对LGFPP复合材料性能的影响

对熔融共混法制备的长玻纤增强聚丙烯(LGFPP)复合材料,在140℃进行0~50 d的热氧老化,考察其微观形貌、结晶性能及力学性能的衰减。力学、SEM、DSC分析结果表明:LGFPP老化50 d后拉伸强度保持率降为83.8%,结晶度由53.5%降低到44.7%。说明基体PP大分子链发生断裂,分子量降低,发生了显著的热氧化降解。SEM测试结果表明:LGFPP复合材料表面出现了明显的微裂纹和表面缺陷。LGFPP静态力学性能下降主要是由于玻璃纤维与PP基体发生界面脱黏以及基体大分子链的断裂。     

LGFPP/IFR复合材料热氧老化性能研究

用熔融共混法制备了长玻纤增强聚丙烯/膨胀阻燃剂(LGFPP/IFR)复合材料,采用热烘箱老化法研究了140℃下老化时间对复合材料热氧老化性能的影响。结果表明:随着老化时间的延长,复合材料的力学性能显著下降,说明其分子量降低,发生了明显的热氧化降解。SEM测试结果表明:LGFPP/IFR复合材料表面出现了明显的网状裂纹,局部还出现了较大的裂纹。PP基体分子链的断裂以及长玻纤与PP基体间发生界面脱黏是导致LGFPP/IFR复合材料宏观力学性能下降的主要原因。     

长玻璃纤维增强聚丙烯复合材料的研究

利用自制的熔体浸渍装置制备了长玻璃纤维增强聚丙烯(PP)复合材料。考察了PP基体流动性、玻璃纤维与PP界面结合强度、玻纤用量对复合材料力学性能的影响。结果表明:PP基体流动性越好,材料的力学性能越高;相容剂的使用会提高玻璃纤维和PP树脂界面的结合强度,从而提高材料的力学性能;材料的力学性能随玻纤用量的增加出现先增大后减小的趋势,当玻纤用量为50%时,复合材料力学性能最佳。     

动态注射成型短玻纤增强高密度聚乙烯力学性能的研究

在不同的振动条件下注射成型短玻纤增强高密度聚乙烯复合材料。实验表明,振动可以有效地改善玻纤在树脂基体中的分散取向状况,提高复合材料的力学性能。与稳态注射成型的复合材料相比,动态注射成型复合材料的拉伸强度最大可提高11.1%,冲击强度最大可提高11.4%。     

汽车用玻纤增强PP的制备及力学性能研究

研究了聚丙烯接枝马来酸酐(PP-g-MAH)用量、基体树脂流动性、玻纤形态和短玻纤的单丝直径对玻纤增强聚丙烯(PP)复合材料性能的影响。结果表明:随着PP-g-MAH用量的增加,复合材料的力学性能呈现先增加后减小的趋势,断面呈韧性断裂。基体树脂PP的熔体流动速率越大,复合材料的力学性能越好。短玻纤比长玻纤直接纱增强效果好,玻纤的单丝直径越细,复合材料的力学性能越好。当PP/PP-g-MAH/其他助剂质量比为67/2/1时,质量分数30%玻纤增强PP复合材料的性能较好。     

短玻纤和连续玻纤增强聚丙烯复合材料的性能比较研究

文分别研究了短玻纤和连续玻纤增强聚丙烯复合材料的性能,讨论了增容剂即马来酸酐接枝聚丙烯(PP-g-MAH)含量、玻纤含量、挤出工艺、玻纤长度等因素对玻纤增强聚丙烯性能的影响。结果表明,PP-g-MAH的加入增强了界面粘接强度,显著提高玻纤增强聚丙烯复合材料的力学性能;适当提高挤出温度和降低螺杆转速可提高玻璃纤维增强聚丙烯复合材料的力学性能;连续玻纤增强聚丙烯复合材料的力学性能大大优于短玻纤增强聚丙烯复合材料的力学性能。     

剑麻纤维与玻纤混杂增强PVC复合材料的性能研究

本文介绍采用短麻纤维(SF)和短玻纤(GF)混杂增强PVC基体,测定了复合材料的弯曲强度、弯曲模量、无缺口冲击强度以及耐水浸泡性能,并探讨了这一复合材料在水浸泡前后的力学性能及其界面行为.结果表明,此种复合材料在弯曲模量和无缺口冲击强度上存在正的混杂效应,而弯曲强度存在负的混杂效应;经水浸泡后,复合材料的弯曲强度、弯曲摸量和冲击强度都有不同程度的下降,而对于纯PVC基体,水浸泡后的弯曲强度和弯曲模量反而有所提高,因此可以认为,水浸泡对纯PVC基体在弯曲性能方面无不良影响,水分主要对纤维与基体的界面产生不良作用,导致复合材料性能下降.     

玻纤增强PVC材料的力学性能及耐热性能

考察了玻璃纤维(简称玻纤)长度、用量和偶联剂表面处理对PVC/玻纤复合材料力学性能和耐热性能的影响。结果表明:与长度3 mm的玻纤相比,长度50 mm的玻纤对PVC材料具有更好的改性效果,用量以15~20份为宜;硅烷偶联剂能显著提升玻纤与PVC基体的界面结合力,从而提高了复合材料的综合性能。     

玻纤增强尼龙6的挤出工艺及力学性能

采用长玻纤连续添加和短切玻纤制备了玻纤增强尼龙6(PA6)复合材料。主要考察了玻纤含量、玻纤种类以及挤出工艺条件对复合材料力学性能的影响,并利用扫描电子显微镜对复合材料的冲击断面和拉伸断面及玻纤形态进行了观察。结果表明,采用短切玻纤加入时,玻纤含量对GF/PA6复合材料的力学性能影响很大。随玻纤含量的增加,复合材料的力学性能越来越高,断裂伸长率变低。加工工艺参数对复合材料的力学性能有影响。采用长玻纤连续添加时,玻纤的添加位置对复合材料的性能影响不大。在玻纤含量相同时,采用长玻纤连续添加得到的材料力学性能明显优于采用短切玻纤时的性能。玻纤能均匀地分散在PA6基体中,玻纤的保留长度和长度分布对复合材料的性能有直接影响。     

纤维增强树脂基复合材料界面粘结强度测试方法探讨

基体和增强材料界面的粘结性能直接影响到复合材料的力学性能，如何测量复合材料界面的粘结强度是界面研究的关键问题之一。本文侧重回顾了目前使用的复合材料界面粘结强度测试方法，如微脱粘、单纤维复合材料断裂、单纤维拔出和压出法，并对相关的计算理论进行了扼要介绍。     

聚丙烯/玻璃纤维的界面改性研究(Ⅳ)--玻璃纤维增强聚丙烯复合材料的界面结构特征

研制高性能的玻璃纤维增强聚丙烯复合材料的关键是提高非极性的聚丙烯和极性的玻璃纤维的界面粘结强度。文章运用溶剂抽提ＦＴ－ＩＲ、ＤＳＣ、ＳＥＭ等分析测试手段对ＦＲＰＰ的理化性能进行了表征,提出玻璃纤维增强聚丙烯复合材料体系的最突出的界面特征是界面剂接枝物与玻璃纤维的相互作用和界面剂接枝物与聚丙烯基体树脂的共结晶。     

Effect of fiber pretreatment condition on the interfacial strength and mechanical properties of wood fiber/PP composites

The effect of fiber surface pretreatment on the interfacial strength and mechanical properties of wood fiber/polypropylene (WF/PP) composites are investigated. The results demonstrate that fiber surface conditions significantly influence the fiber–matrix interfacial bond, which, in turn, determines the mechanical properties of the composites. The WF/PP composite containing fibers pretreated with an acid–silane aqueous solution exhibits the highest tensile properties among the materials studied. This observation is a direct result of the strong interfacial bond caused by the acid/water condition used in the fiber pretreatment. Evidence from coupling chemistry, rheological and electron microscopic studies support the above conclusion. When SEBS‐g‐MA copolymer is used, a synergistic toughening effect between the wood fiber and the copolymer is observed. The V‐notch Charpy impact strength of the WF/PP/SEBS‐g‐MA composite is substantially higher than that of the WF/PP composite. The synergistic toughening mechanisms are discussed with respect to the interfacial bond strength, fiber‐matrix debonding, and matrix plastic deformation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1000–1010, 2000     

聚丙烯/玻璃纤维的界面改性研究(Ⅲ)界面改性的复合效应

研制高性能的玻璃纤维增强聚丙烯复合材料的关键是提高非极性的聚丙烯和极性的玻璃纤维的界面粘结强度。我们认为双马来酰亚胺与聚丙烯 -马来酸酐接枝共聚物并用具有较好的协同效应 ,这与它们之间形成了某种IPN结构有关 ,IPN结构的形成强化了聚丙烯基体的强度 ,也强化了玻璃纤维与聚丙烯基体的界面粘结 ,从而最大程度地提高了复合材料的力学性能     

EOC-g-MAH共混增韧SGF/PP泡沫复合材料的制备及力学性能

采用型内二次发泡工艺制备了马来酸酐接枝乙烯-1-辛烯共聚物(EOC-g-MAH)共混增韧短玻璃纤维(SGF)/聚丙烯(PP)泡沫复合材料,考察了EOC-g-MAH含量对复合材料的泡孔形貌、微观结构和力学性能的影响。结果表明,EOC-g-MAH的引入改善了泡沫体的发泡效果,平均孔径减小约35%,泡孔密度提高近4倍且分布均匀。SGF与基体间的界面结合得到显著增强,且EOC-g-MAH在SGF表面形成了颗粒黏附结构,大幅提高了SGF/PP泡沫复合材料的冲击韧度,并在质量分数为8%时达到最大值,增幅为77%。随着EOC-g-MAH质量分数的增加,SGF/PP泡沫复合材料的抗弯强度先增加后降低,而压缩强度则呈近似线性下降的变化趋势。     

Tensile deformation mechanisms of polypropylene/elastomer blends reinforced with short glass fiber

Polypropylene hybrid composites reinforced with short glass fiber (SGF) and toughened with styrene–ethylene butylenes–styrene (SEBS) elastomer were prepared using extrusion and injection‐molding techniques. Moreover, hybrids compatibilized with SEBS‐grafted maleic anhydride (SEBS‐g‐MA) and hybrid compatibilized with PP grafted with maleic anhydride (PP‐g‐MA) were also fabricated. The matrix of the latter hybrid was designated as mPP and consisted of 95% PP and 5% PP‐g‐MA. Tensile dilatometry was carried out to characterize the fracture mechanisms of hybrid composites. Dilatometric responses showed that the elastic deformation was the dominant deformation mechanism for the SGF/SEBS/PP and SGF/SEBS‐g‐MA/PP hybrids. However, cavitation deformation prevailed over shearing deformation for both hybrids at the higher strain regime. The cavitation strain resulted from the debonding of glass fibers and from the crazing of the matrix in the SGF/SEBS/PP hybrid. In contrast, the cavitation was caused by the debonding of SEBS particles from the matrix of the SGF/SEBS‐g‐MA/PP hybrid. The use of PP‐g‐MA resulting in elastic deformation was the main mode of deformation in the low‐strain region for the SGF/SEBS/mPP and SEBS/SEBS‐g‐MA/mPP hybrids; thereafter, shearing appeared to dominate at the higher strain regime. This was attributed to the MA functional group improving the bonding between the SGF and PP. The correlation between fracture morphology and dilatometric responses also is presented in the article. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 441–451, 2003     

长玻璃纤维增强聚丙烯复合材料的力学性能研究

采用熔体浸渍技术制备了长玻璃纤维母料(LGF/PP-g-MAH/PP)增强聚丙烯(PP)复合材料(LGF/PP)。通过双螺杆挤出机制备了同等配比的短玻纤增强聚丙烯(SGF/PP)复合材料。研究了LGF含量、环氧树脂(EP)和固化剂(2E4MZ)对LGF/PP复合材料的力学性能影响。结果表明:当LGF质量分数为35%～40%时,LGF/PP的综合力学性能最好,且明显优于同样组成的SGF/PP复合材料。EP和含固化剂(2E4MZ)的EP对LGF/PP复合材料的力学性能提高有一定的作用。SEM照片分析表明:EP的加入能改善玻纤与聚丙烯基体的界面粘接。     

PPS/PA66/GF复合材料的制备及性能研究

在聚苯硫醚（PPS）树脂基体中引入聚酰胺66（PA66）,随着PA66含量增加,PPS/PA66共混物的拉伸强度和弯曲强度逐渐下降,结合PPS/PA66共混物的相形貌分析,提出了通过玻璃纤维（GF）的引入,制备具有互锁结构的PPS/PA66/GF三元体系复合材料,达到同时提高复合材料的强度、刚度及韧性的目的。分别考察了短玻璃纤维（SGF）和中长玻璃纤维（LGF）增强PPS/PA66的综合性能。结果表明,GF的引入显著提高了共混物的力学性能,同时,PPS/PA66/SGF和PPS/PA66/LGF复合材料的扫描电子显微镜和动态力学性能分析都表明共混物内部形成了一个高度互锁的结构。     

Improvement in impact property of continuous glass mat reinforced polypropylene composites

The toughened polypropylene (PP) was obtained by the blending of PP with ethylene‐propylene diene monomer (EPDM). The impact property of continuous glass mat‐reinforced polypropylene was adjusted through three ways: different toughness PPs and their blends were used as matrices, the functionalized polypropylene was added into the matrix to control the interfacial adhesion; the ductile interlayer was introduced at the fiber/matrix interphase by the grafting and crosslinking of rubber chains on fiber surface. The effect of PP toughness, interfacial adhesion, and ductile interlayer on the mechanical properties of composite systems was studied. The impact toughness of GMT increased with increasing the matrix toughness, whereas the flexural strength and modulus decreased. The good interfacial adhesion resulted in the low impact toughness. However, GMT composite with high strength, modulus, and impact toughness could be obtained by the introduction of a ductile interlayer at fiber/matrix interphase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2680–2688, 2002     

Process–structure–property relationship in ternary short‐glass‐fiber/elastomer/polypropylene composites

Short‐glass‐fiber (SGF)‐reinforced polypropylene (PP) composites toughened with a styrene/ethylene butylene/styrene (SEBS) triblock copolymer were injection molded after extrusion. Furthermore, a maleic anhydride (MA)‐grafted SEBS copolymer (SEBS‐g‐MA) was used as an impact modifier and compatibilizer. The effects of the processing conditions and compatibilizer on the microstructure and tensile and impact performance of the hybrid composites were investigated. In the route 1 fabrication process, SGF, PP, and SEBS were blended in an extruder twice, and this was followed by injection molding. In route 2, or the sequential blending process, the elastomer and PP were mixed thoroughly before the addition of SGF. In other words, either PP and SEBS or PP and SEBS‐g‐MA pellets were premixed in an extruder. The produced pellets were then blended with SGF in the extruder, and this was followed by injection molding. The SGF/SEBS‐g‐MA/PP hybrid fabricated by the route 2 process exhibited the highest modulus, yield stress, tensile stress at break, Izod impact energy, and Charpy drop weight impact strength among the composites investigated. This was due to the formation of a homogeneous SEBS elastomeric interlayer at the SGF and matrix interface of the SGF/SEBS‐g‐MA/PP hybrid. This SEBS rubbery layer enhanced the interfacial bonding between SGF and the matrix of the SGF/SEBS‐g‐MA/PP hybrid. The correlations between the processing, microstructure, and properties of the hybrids were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1384–1392, 2003     

聚丙烯/玻璃纤维的界面改性研究(Ⅱ)聚丙烯-马来酸酐接枝共聚物的界面改性研究

研制高性能的玻璃纤维增强聚丙烯复合材料的关键是提高非极性的聚丙烯和极性的玻璃纤维的界面粘结强度。本文首次明确提出接枝率、熔融指数、结晶温度是影响聚丙烯 -马来酸酐接枝共聚物作为界面剂使用的关键因素 ,当接枝共聚物的接枝率高、熔融指数大、结晶温度与聚丙烯基体接近时 ,接枝共聚物有较好的界面改性效果 ,可以使用较少量的接枝共聚物使复合材料的力学性能得到最大程度的改善。