高填充竹塑包装盒盒坯注塑成型工艺及性能研究

采用竹纤维与聚烯烃为主要原料,并辅以少量改性与加工助剂,通过同向平行双螺杆挤出造粒线,制备高填充竹塑复合材料颗粒,用于注塑成型包装盒盒坯。研究竹纤维填充量、润滑剂与填料对复合材料加工性能的影响,聚烯烃树脂与填料对成型周期的影响,以及树脂基体、模具温度对包装盒盒坯翘曲变形的影响。研究结果表明:随着竹纤维含量的增加,复合材料的熔融指数快速下降,竹纤维质量分数超过50%后下降速度减缓;润滑剂可以提高复合材料的熔融指数,且内外润滑平衡的复合润滑剂最稳定;滑石粉较碳酸钙更有利于改善复合材料的流动性。聚丙烯比聚乙烯基体复合材料的注塑冷却时间短,滑石粉在缩短冷却时间方面优于碳酸钙。竹塑包装盒盒坯的翘曲变形量随着混合树脂基体中聚丙烯含量的增加而减少,随着模具温度的变化出现波动,最佳模具温度为50℃左右。     

竹纤维质量分数对竹纤维增强聚乳酸复合材料性能影响

以1.5%异氰酸酯(MDI)界面改性剂改性处理后的竹纤维和聚乳酸为原料,通过注射成型工艺制备竹纤维增强聚乳酸复合材料,探讨竹纤维质量分数对复合材料界面、力学性能、吸水率、热性能的影响。结果表明,随着竹纤维质量分数的增加,复合材料拉伸强度、冲击强度、存储模量以及热稳定性均先增大后减小,24h吸水率逐渐增大,损耗因子逐渐降低。竹纤维质量分数为50%时,复合材料的拉伸强度和冲击强度分别达到最大值63.2/MPa和11.6/kJ/m2,复合材料存储模量最大,热稳定性最好。     

竹纤维质量分数对竹纤维增强聚乳酸复合材料性能影响

以1.5%异氰酸酯(MDI)界面改性剂改性处理后的竹纤维和聚乳酸为原料,通过注射成型工艺制备竹纤维增强聚乳酸复合材料,探讨竹纤维质量分数对复合材料界面、力学性能、吸水率、热性能的影响。结果表明,随着竹纤维质量分数的增加,复合材料拉伸强度、冲击强度、存储模量以及热稳定性均先增大后减小,24h吸水率逐渐增大,损耗因子逐渐降低。竹纤维质量分数为50%时,复合材料的拉伸强度和冲击强度分别达到最大值63.2MPa和11.6kJ/m2,复合材料存储模量最大,热稳定性最好。     

皮胶原蛋白粉/低密度聚乙烯的复合性能研究

采用熔融挤出的方法制备得到胶原蛋白/低密度聚乙烯复合材料,并研究了抗氧剂1010(K1010)和交联剂过氧化二异丙苯(DCP)的加入对复合材料性能的影响。结果表明:当加入10%(wt,质量分数,下同)胶原蛋白和0.5%K1010时,复合材料力学性能有一定降低,但热稳定性能和加工流动性能得到明显改善,起到增塑作用;胶原蛋白添加量为10%,DCP含量为2%时,聚乙烯发生了部分交联,拉伸强度达到最大值18.187MPa,断裂伸长率达到最大值246.05%,热稳定性能也有明显增强。     

竹纤维组合形态对竹纤维/聚丙烯复合材料性能的影响

以聚丙烯（PP）为基体,单根竹纤维（SBF）和竹纤维束（BFS）两种形态竹纤维为增强体,采用无纺气流铺装-模压工艺制备了SBF-BFS/PP复合材料。通过力学试验机、SEM、TGA、DSC等对SBF-BFS/PP复合材料的力学性能、微观形貌、热性能等进行表征,研究竹纤维形态配比变化对SBF-BFS/PP复合材料综合性能的影响。结果表明,在纤维总含量不变情况下,SBF在两种形态竹纤维中的含量逐步增加时,SBF-BFS/PP复合材料冲击强度和弹性模量逐步增加; SBF在两种形态竹纤维中质量分数为90wt%时,SBF-BFS/PP复合材料冲击强度和弹性模量比SBF质量分数为10wt%时分别提高了26.46%和38.39%; SEM结果表明,竹纤维与PP基体存在较差界面相容性,竹纤维出现断裂和拔出等现象;热失重结果表明,随着SBF含量的增加,SBF-BFS/PP复合材料的耐热性能并没有明显变化。此外,对SBF-BFS/PP复合材料的耐水性能测试结果表明,由于SBF比表面积大,随SBF含量的增加,SBF-BFS/PP复合材料中易吸水组分增加,从而导致其耐水性能下降。      

物流包装用PP/CSW/hBN复合材料力学及摩擦性能

目的研究不同质量分数六方氮化硼对聚丙烯/硫酸钙晶须复合材料力学性能的影响。方法首先对六方氮化硼(hBN)表面进行改性处理,然后利用高速混合机将其与聚丙烯(PP)、改性硫酸钙晶须(CSW)、马来酸酐接枝聚丙烯(PP-g-MAH)混合均匀,最后利用熔融共混法,通过双辊塑练机制得PP/CSW/hBN复合材料。结果当添加hBN的质量分数为1%~1.5%时,pp/csw/hbn复合材料的力学性能最佳;hBN质量分数为1.5%时,复合材料的摩擦因数和磨损率最低。结论 hBN经过表面改性处理后,其在复合材料中分散性得到了改善,与聚丙烯基体界面间的结合力也得到提高,表现为对聚丙烯复合材料起到了补强、增韧和耐磨的作用。当hBN的质量分数达到一定量时,其在复合材料内部会出现团聚现象,从而降低复合材料的力学性能和摩擦性能。     

二氧化钛对PP/SPTW复合材料性能的影响

目的研究不同质量分数的二氧化钛(TiO_2)对聚丙烯/六钛酸钾晶须复合材料力学性能的影响,并找出TiO_2的最佳质量分数。方法首先采用硅烷偶联剂KH550改性二氧化钛和六钛酸钾晶须(SPTW),然后将改性过的二氧化钛与改性过的六钛酸钾晶须、马来酸酐接枝聚丙烯(PP-g-MAH)、聚丙烯(PP)通过熔融共混法制得PP/PP-g-MAH/SPTW/TiO_2复合材料。结果比较了不同含量二氧化钛对聚丙烯/钛酸钾晶须复合材料性能的影响。研究表明,二氧化钛能够明显改善复合材料的力学性能,随着二氧化钛含量的递增,复合材料的力学性能总体呈先增加后降低的趋势。当二氧化钛质量分数为1%时,复合材料的弯曲强度、拉伸强度和冲击强度分别增大了35.2%,41.2%和33.7%。随着TiO_2质量分数的继续增加,复合材料的弯曲强度逐渐开始下降,拉伸强度和冲击强度在其质量分数超过2%时逐渐开始减小。结论当TiO_2质量分数约为2%时,复合材料的综合力学性能最佳。     

长竹纤维束定向增强聚丙烯复合材料

目的 以我国资源丰富的竹子和聚丙烯（PP）作为原料,研究竹材的预处理和成形工艺对其物理力学性能的影响,扩大竹材的应用领域。方法 通过碱液预处理,对竹条进行软化分丝。然后,利用热压技术将所提取的竹子与聚丙烯进行复合,并调节热压工艺,得出最优参数。结果 使用质量分数为6%的NaOH,在100℃下预处理2.5 h,通过辊压疏解,制备长竹纤维束（LBF）,LBF的抗拉强度为397.2 MPa。经过处理后,LBF/PP复合材料的储能模量达到9.49 GPa,比未处理的LBF/PP复合材料提升了11.5%。确定了最优热压条件：温度为190℃、时间为20 min、压力为6 MPa。随着长竹纤维含量的增加,LBF/PP复合材料的耐水性降低。结论 使用长竹纤维束所制备的LBF/PP复合材料具有优异的物理力学性能,有望作为结构材料应用于集装箱、托盘等,在包装应用领域有较好的前景。     

稻草碎料/聚丙烯复合材料制备及性能研究

以稻草碎料和聚丙烯为主要原料,采用热压成型制备了稻草碎料增强聚丙烯复合材料,研究了NaOH改性剂浓度、稻草碎料质量分数以及热压温度对复合材料力学性能的影响。研究表明,8%NaOH处理可以去除稻草碎料中部分半纤维素,使稻草碎料表面变得粗糙,有效改善了复合材料力学性能;稻草质量分数为40%时,聚丙烯可以有效包覆稻草碎料,复合材料拉伸强度和冲击强度的得到改善;热压温度为180℃时聚丙烯的流动性好,能改善稻草碎料在聚丙烯中分散的均匀性,且不会使聚丙烯热降解。此时,复合材料拉伸强度和冲击强度分别达到了最大值61.2 MPa和18.4kJ/m~2。     

原位形成FPP偶联Al(OH)3/PP复合材料的结构与性能

用熔融挤出一步法制备了原位形成官能团化聚丙烯（FPP）偶联Al(OH)3/PP复合材料，研究了原位形成FPP对Al(OH)3/PP复合材料的结晶与熔融行为，熔融指数，热降解行为，阻燃性能，力学性能和断裂形态等的影响。原位形成FPP使Al(OH)3/PP的结晶温度和熔点降低，熔融指数，拉伸和弯曲强度提高。但对热降解行为和氧指数影响不大。     

Environmental effects on bamboo-glass/polypropylene hybrid composites

The effects of environmental aging and accelerated aging on tensile and flexural behavior of bamboo fiber reinforced polypropylene composite (BFRP) and bamboo-glass fiber reinforced polypropylene hybrid composite (BGRP), all with a 30% (by mass) fiber content, were studied by exposing the samples in water at 25°C for up to 1600 h and at 75°C for up to 600 h. Reduction in tensile strength for BFRP and BGRP was 12.2% and 7.5%, respectively, after aging at 25°C for about 1200 h. Tensile and flexural strength of BFRP and BGRP were reduced by 32%, 11.7%, and 27%, 7.5% respectively, after aging at 75°C for 600 h. While the strengths of the bamboo fiber reinforced composites reduce with sorption time and temperature, the environmental degradation process can be delayed by adding a small amount of glass fiber. Moisture sorption and strength reduction are further suppressed by using maleic anhydride polypropylene (MAPP) as a coupling agent in both types of composite system.     

碱处理对竹纤维及竹纤维增强聚丙烯复合材料性能的影响

为探究竹纤维表面能对纤维与树脂的粘附功及复合材料界面的影响,采用碱处理对竹纤维进行表面改性,通过模压工艺制备了竹纤维增强聚丙烯(PP)复合材料。研究了碱处理对竹纤维性能、竹纤维与PP间的粘附功及对竹纤维/PP复合材料力学性能的影响,采用SEM研究了不同浓度碱处理后竹纤维表面形貌的变化。结果表明:随着碱浓度的增加,竹纤维断裂强度呈现一定波动,当碱浓度为1wt%时竹纤维断裂强度达到最大值;竹纤维与PP的粘附功与竹纤维极性比密切相关,竹纤维极性比越小,粘附功越大;随着碱浓度增大,竹纤维与PP间粘附功与竹纤维/PP复合材料剪切性能呈现相同的趋势,并且都在碱浓度为20wt%时达到最大值,此时竹纤维与PP的粘附功较未处理时提高了67.18%;竹纤维/PP复合材料剪切性能较未处理时提高了23.29%;复合材料弯曲强度在碱浓度为5wt%时达到最大值,相比未处理时提高了23.13%。     

偶联剂对玻璃纤维增强淀粉/聚乳酸复合材料性能的影响

分别以马来酸酐、KH550、KH560和KH570为偶联剂对玻璃纤维进行预处理,再与淀粉、聚乳酸(PLA)复合,通过熔融挤出法制备玻璃纤维增强淀粉/PLA复合材料。研究了偶联剂种类对玻璃纤维增强复合材料熔融指数、力学性能、热性能和熔融流变性能的影响。实验发现马来酸酐、KH550、KH570、KH560处理玻璃纤维增强淀粉/PLA复合材料的熔融指数和力学性能都依次增大,表明KH560处理玻璃纤维增强淀粉/PLA复合材料的界面黏结作用最强。对热性能进行表征发现,马来酸酐、KH550、KH570、KH560处理玻璃纤维增强淀粉/PLA复合材料玻璃化转变温度、重结晶温度、结晶度和热稳定性均依次提高。受玻璃纤维与淀粉/PLA基体界面黏结效果的影响,马来酸酐、KH550、KH570、KH560处理玻璃纤维增强淀粉/PLA体系的储能模量和复数黏度依次增大。     

Influence of carbon nanotube concentration and sonication temperature on mechanical properties of HDPE/CNT nanocomposites

Carbon nanotube (CNT) reinforced high-density polyethylene (HDPE) composites were prepared by a melt mixing procedure. The mechanical properties were analyzed using a central composite design where key factors were CNT concentration and sonication temperature during the sample preparation process. The results indicated that the optimum values were 0.8 wt% for the concentration of CNT and 55°C for the sonication temperature. The samples obtained at optimal conditions were systematically studied. Nanoindentation analysis showed an increase of 43% in Vickers hardness of the nanocomposite when compared to pure polymer. The improvement on the mechanical property is related to changes in the thermo-physical and viscoelastic properties of the nanocomposite.     

Effects of environmental aging on the mechanical properties of bamboo–glass fiber reinforced polymer matrix hybrid composites

Short bamboo fiber reinforced polypropylene composites (BFRP) and short bamboo–glass fiber reinforced polypropylene hybrid composites (BGRP) were fabricated using a compression molding method. Maleic anhydride polypropylene (MAPP) was used as a compatibilizer to improve the adhesion between the reinforcements and the matrix material. By incorporating up to 20% (by mass) glass fiber, the tensile and flexural modulus of BGRP were increased by 12.5 and 10%, respectively; and the tensile and flexural strength were increased by 7 and 25%, respectively, compared to those of BFRP. Sorption behavior and effects of environmental aging on tensile properties of both BFRP and BGRP systems were studied by immersing samples in water for up to 1200 h at 25°C. Compared to BFRP, a 4% drop in saturated moisture level is seen in BGRP. After aging in water for 1200 h, reduction in tensile strength and modulus for BGRP is nearly two times less than that of BFRP. Use of MAPP as coupling agent in the polypropylene matrix results in decreased saturated moisture absorption level and enhanced mechanical properties for both BFRP and BGRP systems. Thus it is shown that the durability of bamboo fiber reinforced polypropylene can be enhanced by hybridization with small amount of glass fibers.     

改性透辉石增强聚乙烯复合材料的研究

采用硬脂酸和铝酸酯两种改性剂对超细透辉石粉体进行表面改性,通过接触角和活化指数评价表面改性效果,同时利用熔融共混塑化成型法制备透辉石/聚乙烯复合材料,探讨了不同偶联剂对复合材料力学性能的影响。用SEM观察了其在聚乙烯基体中的分散情况,用X射线衍射仪对复合材料的结晶状况进行了表征。结果表明,经过适当表面处理的透辉石可以通过共混均匀分散在聚乙烯中,粒子与基体界面结合良好,复合材料的力学性能得到一定的提高,从而降低生产成本。     

Factorial study of material and process parameters on the mechanical properties of extruded kenaf fibre/polypropylene composite sheets

Thin kenaf/polypropylene (PP) composite sheets were manufactured via extrusion. The effects of kenaf and maleated PP (MAPP) proportions, fibre length, PP melt flow index (MFI) and die temperature on tensile, flexural, in-plane and out-of-plane shear properties were analysed by conducting experiments through ‘design of experiments’ methodology. Higher kenaf content and lower die/barrel temperatures resulted in composite sheets with higher average mechanical properties in various modes of testing. Matrix MFI appeared to significantly affect all mechanical properties. It is interesting to note that the properties of the very short-fibre composites produced are comparable to those reinforced with longer discontinuous fibres and long-fibre mats.     

A novel process to improve yield and mechanical performance of bamboo fiber reinforced composite via mechanical treatments

The aims of the present study are to produce bamboo fiber reinforced composite (BFRC) with high yield and to investigate the mechanical properties of BFRC comparing with those of commercial bamboo scrimber (BS) and laminated bamboo lumber (LBL). A novel process was developed for production of BFRC using oriented bamboo fiber mat (OBFM) made by a pilot machine. The yield and the mechanical properties of BFRC were investigated and analyzed in comparing with those of raw bamboo and other bamboo-based composites. The results show that the novel process produces 92.54% yield of OBFM due to without any chemical and special removing of inner and outer layer of bamboo during processing. In addition, all the mechanical properties and the variability of BFRC were significantly enhanced comparing with those of raw bamboo and other bamboo-based composites.     

Bamboo fiber reinforced thermoplastic molding made of steamed wood flour

To improve the mechanical property of moldings made of steamed wood flour, layered wood moldings reinforced with steam-exploded bamboo fiber was prepared. Setting the bamboo fiber weight fractions at 25, 50, and 75%, and number of layers at three-, five-, and seven-layered wood moldings were prepared by compression molding. The results of tensile test showed that the tensile strength as well as Young’s modulus increased along with the increase in the bamboo fiber fractions. Where the bamboo fiber content was 75%, the tensile strength became approximately 3.8 to 5.8 times greater, and the tensile Young’s modulus became approximately 2.5 times greater when compared to moldings of 100% wood flour. This fact shows that bamboo fiber is effective to improve the mechanical property of wood moldings. In addition, the tensile strength also increased as the number of layers increased. This result suggested that interfacial shear stress was produced between the layers of bamboo fiber and wood flour.     

Gaining knowledge on the processability of PLA-based short-fibre compounds – A comprehensive comparison with their PP counterparts

The present study provides a quantitative overview of bio-based compound processing compared to commonly used composites reinforced with short glass fibres (GF). Three reinforcing fibres were compounded with polylactide and polypropylene: abaca, man-made cellulose and conventional E-GF. The flow behaviour of corresponding melts was determined using melt flow rate (MFR) and online flow spiral test. The composite structures were analysed by means of SEM in order to investigate the fibre fracture during processing and the fibre/matrix bonding affinity. The fibre length distribution was correlated with the results from the melt flow experiments, and the structure–property relationships were determined using SEM images. It was confirmed that the fibre texture, interactions between fibres and fibre–matrix bonding are influenced by subsequent processing steps and have a substantial effect on the further composite melt processing.