甘蔗渣纤维增强聚丙烯复合材料的制备和力学性能

利用注射成型制备了甘蔗渣纤维增强聚丙烯复合材料, 分析了纤维质量分数、 注射成型条件以及添加物对复合材料力学性能的影响。结果表明, 随着纤维质量分数的增加, 材料的弯曲模量呈递增趋势。由于甘蔗渣纤维热降解的发生, 材料的力学性能随筒体温度的增加呈下降趋势。在模具温度90℃、 注射间隔时间30s、 不同的筒体温度185℃和165℃的成型条件下, 材料的弯曲性能和冲击强度分别呈现最大值。添加了马来酸酐改性聚丙烯后, 材料的弯曲强度和冲击强度得到了提高。      

氮化硼导热复合材料的制备与性能

以聚丙烯为基材,六方氮化硼为填料,添加马来酸酐接枝聚丙烯,利用双螺杆挤出机制备导热复合材料。采用X射线衍射、扫描电子显微镜表征材料的微观结构,对复合材料的结晶性能、力学性能和导热性能进行分析。结果表明,马来酸酐接枝聚丙烯有利于增加聚丙烯与氮化硼的界面粘结,改善复合材料的结晶,增强复合材料拉伸强度和断裂伸长率,显著提高其热导率。氮化硼含量为30%(质量分数)时,添加马来酸酐接枝聚丙烯的复合材料热导率为0.512 W/(m·K),相对于只添加氮化硼的复合材料和聚丙烯,热导率分别提高1.08和2.3倍。     

马来酸酐/丙烯酸丁酯双单体接枝聚丙烯

采用熔融法进行马来酸酐(MAH)和丙烯酸丁酯(BA)双单体接枝聚丙烯(PP)的研究。结果表明,在一定工艺条件下,仅添加一单体马来酸酐时,接枝率G在其加入量为4%(质量分数)时达到最大(0.65 mmol/g PP);马来酸酐添加量保持不变,接枝率随第二单体丙烯酸丁酯添加量增加而出现一极值(1.34 mmol/g PP),比一单体接枝聚丙烯的接枝率高出一倍,并高于文献值(0.36 mmol/g PP)。经红外光谱、热失重分析和差示扫描量热分析表明,马来酸酐、丙烯酸丁酯均与聚丙烯发生接枝反应,并且以短支链的形式连接在PP的主链上。     

反应挤出马来酸酐接枝聚甲基乙撑碳酸酯的结构与热性能

通过反应挤出制备马来酸酐接枝聚甲基乙撑碳酸酯(PPC-g-MA),采用红外光谱分析、滴定法、溶液黏度测试等方法表征了PPC-g-MA的结构,通过热重分析和稳态粘弹流变性能测试,研究了接枝物的热性能,分析了PPC-g-MA结构与热性能的关系。PPC-g-MA的红外谱图显示在1640cm-1处出现碳碳双键伸缩振动吸收峰,说明MA成功接枝到PPC主链上。MA添加量由0.5phr增加至5phr,PPC-g-MA的接枝率、特性黏度和热稳定性先提高后降低。当MA添加量为0.5phr时,PPC-g-MA的接枝率为0.224%,此时产物的初始分解温度(T-5%)比纯PPC升高了8.2℃,特性黏度提高了1.22,复数黏度降低10%所消耗的时间延长了1875s;当MA添加量增加到1phr时,PPC-g-MA的接枝率和T-5%同时达到最大值,分别为0.284%和264.8℃。研究表明当MA添加量低于1phr时,产物的接枝率和特性黏度高,可提高PPC热性能。     

麦秸纤维/废旧塑料再生复合材料

研究了偶联剂KH550、麦秸纤维以及相容剂MAH-g-PP的添加量对麦秸纤维/废旧聚丙烯复合材料力学性能的影响.通过FT-IR检测了偶联剂浓度对麦秸纤维微观组织结构的影响,采用SEM观察复合材料的冲击断口形貌,以研究麦秸纤维与废旧聚丙烯间的相容性.结果表明:经浓度为1.5%的KH550处理过的麦秸纤维极性最低,与废塑料基体的结合性最好;随着麦秸纤维含量的增加,材料的拉伸强度降低,冲击强度稍有提高;当MAH-g-PP含量为4%时,复合材料的拉伸、冲击强度最大.     

基于响应曲面法的木塑复合材料强度分析及挤出工艺优化

以杨木纤维(WF)为增强材料,以高密度聚乙烯(HDPE)为基体,马来酸酐接枝聚乙烯(MAPE)为偶联剂,采用熔融挤出法制备了WF/HDPE复合材料。选取WF含量、偶联剂添加量、挤出温度为自变量,试件的抗冲击强度、弯曲强度、拉伸强度为响应值,采用Box-Behnken Design方法设计实验并利用响应曲面法建立WF/HDPE复合材料力学强度的二次多项数学模型,对WF/HDPE复合材料的挤出工艺进行优化设计。结果表明,WF添加量、MAPE添加量和挤出温度的最佳水平为:47.37wt%、4.23wt%、173.69℃,此时WF/HDPE复合材料的抗冲击强度为4.06 kJ·m?2,弯曲强度为43.79 MPa,拉伸强度为28.59 MPa。模型预测值与实测值误差小于5%,较好地反映了WF/HDPE复合材料力学性能与挤出工艺因素间的关系。      

基于正交实验方法优化PP/PLA复合材料薄膜力学性能研究

随着现代社会对多功能材料需求的增大,针对杂化复合材料的研究也不断深入。为了得到可生物降解的环保型杂化复合材料,本文将传统合成聚合物聚丙烯(Polypropylene,PP)和生物可降解材料聚乳酸(Polylactic acid,PLA)进行熔融共混,并加入马来酸酐(Maleic anhydride,MAH)进行增容,制备出PP/PLA杂化复合材料薄膜。将PP/PLA杂化复合材料薄膜力学性能作为评定标准设计正交实验,影响因素包括混合时间、马来酸酐添加量以及螺杆转速,每个因素设置三个水平。通过方差与极差分析得出马来酸酐添加量为最显著因素,并单独对其进行单因素分析,以确定最佳添加量。最终得出PP/PLA杂化复合材料薄膜最优工艺为混合时间8 min,马来酸酐添加量0.8wt%,螺杆转速130 r/min,此条件下其拉伸强度与弹性模量分别可达到25.08 MPa和1 288.74 MPa,比未添加马来酸酐时分别提升了100%和140%。     

增容剂对聚丙烯基木塑复合材料性能影响研究

利用熔融法、溶液法制备聚丙烯接枝丙烯酸(PP-g-AA)、乙烯-辛烯共聚物接枝马来酸酐(POE-g-MAH)、聚丙烯接枝马来酸酐(PP-g-MAH)_3种大分子增容剂,用来改善木塑复合材料相容性问题。考察其对复合材料的力学性能、流变性能以及材料吸水性的影响。结果表明,添加PP-g-AA、POE-g-MAH和PP-g-MAH作为增容剂,木塑复合材料的性能都有所提高。其中,溶液法制得的增容剂,效果显著。当添加10%(wt,质量分数)溶液法制得的PP-g-MAH,木塑复合材料的拉伸强度为25.21MPa,冲击强度为4.014kJ/m~2,复合材料的扭矩达到5.8N·m,吸水率低至0.9%。     

木质素磺酸铵对聚乳酸/木纤维可生物降解复合材料力学与热性能的影响

为探讨生物质资源改善复合材料的界面及综合性能的可行性,以木纤维(WF)为基体,聚乳酸(PLA)为增强体,添加氧化改性木质素磺酸铵(OMAL),采用高速混合-平板热压工艺制备环境友好型OMAL-PLA/WF复合材料。研究了OMAL对OMAL-PLA/WF复合材料力学和热性能的影响。结果表明:在WF与PLA质量比为7∶3的复合体系中,OMAL对提高OMAL-PLA/WF复合材料的静曲强度、弹性模量以及内结合强度具有促进作用。OMAL添加量为15wt%~20wt%时,OMAL-PLA/WF复合材料的力学性能最好;当OMAL添加量为20wt%时,与PLA/WF对照样相比,OMAL-PLA/WF复合材料的热分解起始温度降低45℃,热分解速率特征峰温度提前107℃,残渣量增加5.3%,玻璃化转变温度、冷结晶温度和熔融温度均向低温方向移动,储能模量和损耗角正切值增大,玻璃态阶段的热稳定温度范围提高约20℃。     

SPTW 对聚丙烯复合材料力学性能的影响

目的研究六钛酸钾晶须添加量的不同对聚丙烯复合材料力学性能的影响。方法采用硅烷偶联剂KH550改性六钛酸钾晶须(SPTW),利用熔融共混法,将改性过的六钛酸钾晶须与聚丙烯(PP)、马来酸酐接枝聚丙烯(PP-g-MAH)熔融共混制得PP/PP-g-MAH/SPTW复合材料。结果比较不同含量的六钛酸钾晶须对复合材料力学性能的影响,发现添加适量改性过的六钛酸钾晶须可明显改善复合材料的力学性能。随着六钛酸钾含量的不断增加,其弯曲强度也增大,当SPTW的质量分数为12%时,弯曲强度提高了21.5%,随着含量的继续增加,弯曲强度开始下降;其拉伸强度和冲击强度都呈先增加后降低的趋势,在SPTW质量分数为8.3%左右时,其拉伸强度和冲击强度分别提高了19.7%和31.8%。结论在聚丙烯中添加经硅烷偶联剂KH550改性的SPTW,其质量分数为12%时,力学性能最佳。     

Characterization and biodegradability of polypropylene composites using agricultural residues and waste fish

The objective of this research was to study the potential of waste agricultural residues such as rice-husk fiber (RHF), bagasse fiber (BF), and waste fish (WF) as reinforcing and biodegradable agents for thermoplastic composites. Addition of maleic anhydride grafted polypropylene (MAPP) as coupling agent was performed to promote polymer/fiber interfacial adhesion. Several composites with various polypropylene (PP) as polymer matrix, RHF, BF, WF, and MAPP contents were fabricated by melt compounding in a twin-screw extruder and then by injection molding. The resulting composites were evaluated through mechanical properties in terms of tensile, flexural, elongation at break and Izod notched impact following ASTM procedures. Biodegradability of the composites was measured using soil burial test in order to study the rates of biodegradation of the composites. In general, the addition of RHF and BF promoted an increase in the mechanical properties, except impact strength, compared with the neat PP. According to the results, WF did not have reinforcing effect on the mechanical properties, while it could considerably improve the biodegradation of the composites. It was found that the composites with high content of WF had higher degradation rate. Except impact strength, all mechanical properties were found to enhance with increase in cellulosic fiber loading In addition, mechanical properties and biodegradability of the composites made up using RHF was superior to those of the composites fabricated with BF, due to its morphological (aspect ratio) characteristics.     

Dynamic and steady state viscoelastic behavior and morphology of MAPP treated PP/sisal composites

The present paper summarizes an experimental study on the molten viscoelastic behavior of PP/sisal composites under steady and dynamic state. Variations in melt viscosity and die swell of the composites with an increase in shear rate, fibre loading and coupling agent concentration have been investigated using capillary rheometer. It was observed that with the addition of sisal fibers and MAPP, the melt viscosity of the composites increased due to improved fiber–matrix interfacial adhesion. Further the dynamic viscoelastic behavior measured, employing parallel plate rheometer revealed an increase in the storage modulus (G′) indicating higher stiffness in case of fibre filled composites as compared with the virgin matrix. Time temperature superposition was applied to generate various viscoelastic master curves. The fiber–matrix morphology of the extrudates was also examined using scanning electron microscopy, which corroborated the findings of the rheological properties. The extrudate cross sections of the composites displayed uniform distribution of fibers within the PP matrix with lesser surface irregularities at high shear rates.     

汽车内饰用秸秆纤维/聚丙烯复合材料流变本构方程的建立

以秸秆纤维/聚丙烯(PP)母粒和PP为主要原料,利用双螺杆挤出机共混挤出造粒制备了不同纤维含量的汽车内饰用秸秆纤维/PP复合材料。通过对复合材料的压力-比容-温度(PVT)特性和黏度特性进行测试分析,建立了不同秸秆纤维含量的秸秆纤维/PP复合材料的PVT曲线和黏度曲线,探讨了纤维含量对材料PVT特性和黏度特性的影响规律。分别使用修正的双域Tait状态方程和Cross-WLF黏度方程对PVT曲线和黏度曲线进行参数拟合;基于拟合结果的分析,最终建立了考虑秸秆纤维含量影响的修正PVT模型与黏度方程。基于Moldflow分析软件建立了材料属性文件,对某汽车门饰板进行了模流分析。结果表明,建立的复合材料流变方程可有效用于注塑成型数值模拟分析。      

Influence of compatibilizing system on morphology,thermal and mechanical properties of high flow polypropylene reinforced with short hemp fibers

Simultaneous influence of polypropylene-graft-maleic anhydride (MAPP) and silane-treated hemp fibers (HF) on morphology, thermal and mechanical properties of high-flow polypropylene (PP) modified with poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) was studied in this paper. The addition of SEBS reduced the efficiency of MAPP in PP composites with HF, thus silane-treated fibers (HFs) were used to improve polymer–fiber interface. Thermal stability of HF was improved after silane treatment and less than 2% weight loss was observed at 240 °C in composites with 30 wt% HF. Better dispersion of fibers and better efficiency in enhancing static and dynamic mechanical properties of PP, doubling its strength and stiffness were observed in composites with treated fibers compared to untreated ones. High ability to absorb and dissipate energy and well-balanced strength and stiffness were showed by PP modified with SEBS and MAPP containing 30 wt% HFs. These composites were studied as an alternative to conventional PP/glass fibers composites for injection molding of small to medium auto parts.     

硼酸锌含量对麦秸秆/PP复合材料耐霉菌腐蚀性能的影响

为探讨防霉剂硼酸锌对麦秸秆/聚丙烯(PP)复合材料耐霉菌腐蚀性能的影响,对添加不同含量硼酸锌的麦秸秆/PP复合材料进行了霉菌加速腐蚀实验。测试其腐蚀后的力学性能、颜色变化和吸水性,采用FTIR分析其官能团的变化,采用体视显微镜观察并分析复合材料表面霉菌生长情况及表面微观结构。结果表明:硼酸锌对麦秸秆/PP复合材料耐腐蚀性能有较好的改善作用,硼酸锌最佳添加量为2wt%,麦秸秆/PP复合材料腐蚀后表面霉菌生长较少,其弯曲强度、弯曲弹性模量、拉伸强度和冲击强度比不添加硼酸锌分别提高6.5%、50.2%、6.8%和11.1%,吸水率和色差值降低23.9%和30.7%。含量为2wt%的硼酸锌能够有效阻止霉菌菌丝腐蚀麦秸秆/PP复合材料的麦秸秆纤维素和半纤维素,而硼酸锌含量较高时会影响复合材料的界面,导致界面处麦秸秆纤维更易受霉菌腐蚀作用。     

聚丙烯/有机蒙脱土纳米复合材料的制备及性能

以马来酸酐接枝低分子量的聚丙烯(M APP)为相容剂,采用熔融插层法,制备了聚丙烯(PP)/有机蒙脱土(OMM T)纳米复合材料;采用微机控制电子万能试验机、悬臂梁冲击试验机研究了复合材料的力学性能;采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和偏光显微镜(POM)等对复合材料的微观结构进行了研究。结果表明,熔融插层法能够获得较好的插层效果,适量蒙脱土的加入使聚丙烯的球晶数量增多,球晶尺寸变小;复合材料的拉伸强度和冲击强度都是先增加后降低,总体上来说,拉伸强度高于纯聚丙烯,冲击强度与纯聚丙烯相近。     

麦秸秆粉/PP木塑复合材料紫外线加速老化性能

以麦秸秆粉为填充材料(质量分数50%),以聚丙烯(PP)膜为基体材料,采用混炼模压成型制备麦秸秆/PP木塑复合材料,对其进行紫外线加速老化实验,对比研究不同填充材料的木塑复合材料老化前后的力学性能和颜色变化,用FTIR分析探讨了复合材料老化机制,用SEM观察其表面微观形貌。结果表明,紫外线加速老化会导致麦秸秆/PP复合材料力学性能降低,当老化时间小于960 h时,麦秸秆/PP木塑复合材料弯曲强度、拉伸强度下降幅度较小,老化时间大于960 h时,力学性能下降幅度较大,材料褪色明显; 老化1200 h其弯曲强度、拉伸强度、冲击强度分别下降67.2%、47.89%、32.41%; 麦秸秆纤维中羟基加速了PP的紫外光降解,最终材料表面出现明显裂纹,部分纤维剥落并伴随有PP粉化现象。     

PEN短纤维增强PTT复合材料的流变性能及力学性能

研究了聚对苯二甲酸丙二酯(PTT)/聚对萘二甲酸乙二酯(PEN)短纤维复合材料的流变行为和力学性能,讨论了复合材料的组成、剪切应力和剪切速率及温度对熔体流变行为、熔体黏度的影响,以及不同配比复合材料的力学性能。结果表明,PTT/PEN短纤维复合材料熔体为假塑性流体,熔体表观黏度随着温度升高而下降,且熔体黏度随着PEN短纤维含量增加而不断上升。随PEN短纤维加入量的增加,复合材料的拉伸强度、断裂强度、弹性模量均明显提高,无缺口冲击强度略有提高,说明PEN短纤维的加入对PTT起到了明显的增强作用而不降低材料的韧性。     

非均质秸秆纤维复合材料保险杠蒙皮刚度分析

目的 研究非均质秸秆纤维复合材料保险杠蒙皮的刚度性能.方法 采用试验与模拟分析的方法,通过共混挤出与化学发泡注塑工艺制备微发泡秸秆纤维/聚丙烯(SF/PP)复合材料试样,通过试验测试非均质结构试样的力学性能与微观结构,通过有限元分析手段建立非均质微发泡秸秆纤维/PP复合材料结构分析模型,并分析非均质材料保险杠蒙皮的刚度...     

Micromechanical deformation processes in PP/wood composites: Particle characteristics,adhesion, mechanisms

Polypropylene (PP) was reinforced with four natural fillers having different particle characteristics. Interfacial adhesion was changed by the introduction of maleated polypropylene (MAPP). The properties of the studied PP/wood composites depended strongly on interfacial adhesion and on the particle characteristics of the wood. Coupling with functionalized polymer is necessary for the preparation of composites with acceptable properties if the size of the particles is large and their aspect ratio is small. The effect of adhesion is smaller for particles with large aspect ratio. Several micromechanical deformation processes may occur in PP/wood composites including matrix yielding, debonding, fiber pull-out and fiber fracture both parallel and perpendicular to the fiber axis. The processes are competitive and may take place simultaneously and/or consecutively. The inherent properties of the reinforcement may limit the improvement of composite strength. Micromechanical deformation processes determine composite properties irrespectively of their mechanism.