木塑复合材料抗菌性能研究

以高密度聚乙烯和木粉为主要原料,采用热压成型的方法制备了4种不同木粉含量的木塑复合材料。通过测量复合材料腐蚀前后的质量变化、弯曲强度、色差和表面形貌等,研究了木粉含量对木塑复合材料抗菌性能的影响。结果表明:木塑复合材料在密粘褶菌中会发生腐蚀;木粉含量越高,木塑复合材料越容易被腐蚀;腐蚀的主要是木纤维,而塑料不易被腐蚀。     

木粉含量对木粉-淀粉/聚乳酸复合材料性能的影响

以杨木粉、玉米淀粉和聚乳酸(PLA)为原料,甘油为相容剂,利用熔融挤出法制备了木粉-淀粉/PLA复合材料。研究了木粉含量对复合材料界面相容性、热性能、力学性能、流变性能以及吸水率的影响。结果表明:随着木粉含量的增加,PLA与木粉之间的界面相容性下降,木粉-淀粉/PLA复合材料的热稳定性下降,储能模量、损耗模量和复数黏度逐渐增加;随着木粉含量的增加,木粉-淀粉/PLA复合材料的拉伸强度和弯曲强度呈现先增大后减小的趋势,当木粉含量为18wt%时,复合材料的拉伸强度和弯曲强度均达到最大值,最大值分别为40.65 MPa和60.91 MPa;随木粉含量的增加,复合材料的断裂伸长率由9.64%减小到5.97%,而吸水率由5.38%增大到13.43%。     

木粉/PE复合材料与高速钢刀具摩擦特性的研究

目的 切削加工时木工刀具的摩擦磨损形式较为复杂,旨在研究高速钢与木粉/PE复合材料之间的摩擦特性.方法 通过木粉/PE复合材料与高速钢的摩擦试验,围绕木粉质量分数、往复频率、轴向载荷等因素,分析木粉/PE复合材料与高速钢摩擦因数的变化规律,以及试验后木粉/PE复合材料的表面形貌.结果 木粉/PE复合材料与高速钢刀具的摩擦因数随着木粉质量分数的增加呈现出先升高再降低的趋势,在木粉质量分数为50％时达到最大,摩擦特性为磨粒摩擦及粘着摩擦.结论 随着频率、载荷的升高,木粉质量分数较高的木粉/PE复合材料摩擦因数明显降低,高速钢刀具更适用于切削加工木粉质量分数较高的木粉/PE复合材料;摩擦试验后木粉/PE复合材料粗糙度显著降低,使用高速钢刀具切削加工木粉/PE复合材料,木粉质量分数为50％的材料试验后形貌较为平整,这为获得较好的表面切削质量提供了有力参考.     

木粉含量对木粉/酯化淀粉/聚乳酸复合材料性能影响

以甘油为相容剂,利用木粉、马来酸酐酯化淀粉和聚乳酸(PLA)进行熔融挤出制备了木粉/酯化淀粉/聚乳酸复合材料。利用XRD和SEM对复合材料的结晶度和断面形貌进行分析表征,以研究木粉含量对复合材料界面相容性的影响;并对复合材料的热稳定性、力学性能、流变性能以及吸水率进行表征。实验结果表明,随着木粉含量的增加,复合材料的界面相容性下降,拉伸强度和弯曲强度增大,断裂伸长率下降,吸水率逐渐增大;TGA测试结果表明木粉的加入使材料的热稳定性下降;流变测试表明木粉用量的增加,使复合材料的储能模量、损耗模量和复数粘度逐渐增加。     

木粉原位接枝共聚共混制备复合材料

在乳酸和木粉的非均相体系中,乳酸脱水生成的丙交酯,和桑树木粉中含有羟基的高聚物进行原位接枝共聚生成木粉接枝聚乳酸(Wood-g-PLA),体系中同时生成的均聚乳酸(PLA)与Wood-g-PLA原位共混得到Wood-g-PLA/PLA复合材料.用红外光谱对改性木粉与原料木粉进行对比分析,表明木粉表面被成功接枝改性.利用SEM、TG、万能力学试验机等仪器分析了改性木粉/聚乳酸复合材料的界面相容性以及热、力学性能,发现材料中Wood-g-PLA与聚乳酸融为一体无相分离现象.Wood-g-PLA含量对复合材料的拉伸强度有一定影响,但对弯曲强度影响不大.材料力学性能有待提高.     

ABS木塑复合材料的制备与研究

以丙烯腈-丁二烯-苯乙烯共聚物(ABS)塑料为基体,木粉和纳米蒙脱土为填料,采用双螺杆挤出造粒后模压成型工艺制备高性能ABS木塑复合材料。研究了木粉、纳米蒙脱土、界面相容剂ABS接枝马来酸酐(ABS-g-MAH)含量等对ABS木塑复合材料力学性能的影响和SEM分析。结果表明:木粉含量为50%(wt,质量分数,下同),纳米MMT含量为10%,ABS-g-MAH含量为2%时,ABS木塑复合材料的力学性能最佳,弯曲强度达到69MPa、弯曲模量达到5900MPa和冲击强度达到17kJ/cm~2。从材料的SEM图观察到,加入木粉、纳米MMT和ABS-g-MAH后材料的界面相容性得到提高,增强了材料的力学性能。     

PBS/杨木粉全降解木塑复合材料的加工流变性能及其应用研究

采用高级毛细管流变仪,分别测定PBS及PBS/杨木粉全降解木塑复合材料的流变性能,研究了不同挤出温度、不同木粉含量对复合材料加工性能的影响。以流变性能测试为参考,改变加工工艺,采用熔融共混法制备了PBS/杨木粉全降解木塑复合材料,并测试其性能。结果表明,随着木粉用量的增加,体系流动性明显下降,可加工的温度范围越来越窄,大致木粉填充量每提高5%,需要升高5℃才能保证粘度变化不大;不同加工工艺对所制备的PBS/杨木粉木塑复合材料性能有较大影响;综合流变性能和力学性能,木粉含量为30%、35%、40%、45%和50%的PBS/杨木粉全降解木塑复合材料的较佳加工温度分别为120、125、125、130和135℃。     

聚乳酸/木粉复合材料的力学及吸水性能研究

采用聚乳酸（PLA）及偶联剂马来酸酐（MAPP）对木粉进行改性,研究采用熔融共混方法制备的聚乳酸/木粉复合材料的力学性能、吸水性能、微观特性,以及宏观与微观之间的联系。研究结果表明力学性能方面,随着木粉含量从10g增加到25g,最大拉力增加了4倍,抗拉强度增加了3倍;偶联剂使用后,最大拉力和抗拉强度较未使用前最大增加值都超过了1倍。吸水性能方面,随着木材成分的增加,复合材料的吸水率同时增加,2和24h增重最多分别为2.85%和8.12%;偶联剂的使用降低了复合材料的吸水率,2和24h增重最多分别为0.72%和3.58%。最后使用电子扫描显微镜（SEM）观察发现同样木粉含量,添加偶联剂后界面更加光滑,PLA与木粉之间的粘合更紧密。     

聚乳酸木塑复合材料增韧研究进展

聚乳酸(PLA)和木粉复合而成的PLA木塑复合材料,能有效解决PLA性脆、韧性差的问题,得到韧性较好的可降解复合材料。通过添加相容剂或偶联剂提高复合材料界面相容性,同时研究木粉组分、含量、粒径,得到PLA木塑复合材料增韧改性的成果,并分析研究了改性后复合材料的结晶性能,最后展望了PLA木塑复合材料的发展前景。     

木粉对聚乳酸流变、结晶及发泡行为的影响

以超临界CO_2为发泡剂,设计高温保压、低温快速泄压发泡的工艺,制备微孔发泡木粉/聚乳酸复合材料。利用X射线衍射仪、差示扫描量热仪、旋转流变仪对复合体系结晶及流变性能进行分析。采用排水法及扫描电镜研究了木粉含量对发泡材料表观密度、发泡倍率,泡孔密度及泡孔形貌的影响。结果表明,木粉的加入提高了木粉/聚乳酸复合材料熔体的复数黏度和储能模量,降低了聚乳酸的结晶度,提高了泡孔密度,减小了泡孔尺寸。当木粉含量为20%时,木粉/聚乳酸发泡材料表观密度为0.19g/cm~3,发泡倍率达到7倍,泡孔密度为7.23×10~8 cm~(-3),平均泡孔直径为20μm。     

Influence of wood flour moisture content on the degree of silane-crosslinking and its relationship to structure–property relations of wood–thermoplastic composites

The objective of this work was to examine how the moisture content of wood flour affects the degree of crosslinking when producing silane-crosslinked wood–thermoplastic composites. Crosslinked composites were produced by adding a silane solution to the compounding process of wood flour and polyethylene. Crosslinked composites of pre-dried as well as non-dried wood flour were prepared and their degree of crosslinking at various storage conditions was determined. Mechanical properties and the creep response of the crosslinked composites were tested in order to establish structure–properties relations. The results showed that all crosslinked composites displayed higher strengths and lower creep responses compared with non-crosslinked control samples. However, the degree and rate of crosslinking proved to be lower when a larger amount of moisture was present in the compounding process. It was concluded that the silane-grafting yield was lower when wood flour of a higher moisture content was used.     

木粉/聚丙烯木塑复合泡沫材料吸能特性

采用模压法制备木粉/聚丙烯复合泡沫材料,并对不同木粉含量的泡沫材料进行静态压缩、循环压缩、压缩蠕变、动态热机械分析的测试,探讨了不同木粉含量的木粉/聚丙烯复合泡沫材料的能量吸收效果。结果表明: 随着木粉含量的增加,木粉/聚丙烯木塑复合泡沫材料的能量吸收量、能量吸收效率参数、松弛率、循环损耗量、动态力学性能等均呈先升后降的趋势,在木粉质量比为30%时泡沫材料吸能性能达到最佳。     

Creep behavior and manufacturing parameters of wood flour filled polypropylene composites

The influence of wood flour content, coupling agent and stress loading level on the creep behavior of wood flour–polypropylene composites was investigated. Maleated polypropylene (MAPP; Epolene G-3003™) was used as the coupling agent to treat the wood flour used as reinforcing filler for polypropylene composite. The tensile strength and modulus of various wood flour–polypropylene composites (WPCs), manufactured using the melt blending, extrusion, and palletizing methods, were measured before performing the creep test. The residual tensile strength, creep strain, and fractional deflection of the resultant wood flour–polypropylene composites were measured by means of the creep test. It was shown that the tensile strength decreased with increasing wood flour level in the composites. The creep strain also decreased as the wood flour level increased. The presence of the coupling agent increased the tensile strength of the wood flour–polypropylene composites, compared with the specimens made of pure polypropylene. For those composites containing the coupling agent, the creep deflection was significantly lower than those made without any coupling agent. The creep strains of the WPC specimens observed during the creep test fitted perfectly with the four-element burger creep model. Further investigation is required of the effects of combined mechanical and environmental loading in varying proportions.     

玻璃纤维含量对竹粉/高密度聚乙烯复合材料性能的影响

为利用玻璃纤维提高木塑复合材料的综合性能,探讨玻璃纤维含量对竹粉/高密度聚乙烯(HDPE)复合材料性能的影响规律,首先,采用A-171硅烷偶联剂对竹粉表面进行了改性,并加入了一定量的玻璃纤维;然后,采用热压成型工艺制备了玻璃纤维-竹粉/HDPE复合材料;最后,考察了玻璃纤维含量对复合材料力学性能、热学性能及摩擦学性能的影响,并利用SEM观察材料的断面和磨损表面形貌。结果表明:当玻璃纤维含量为3wt%时,能显著提高竹粉/HDPE复合材料的拉伸强度和弯曲强度,与未添加玻璃纤维的复合材料相比,添加玻璃纤维后复合材料的拉伸强度和弯曲强度分别提高了19.41%和23.54%;在30~60℃温度范围内,复合材料长度-宽度方向上的线膨胀系数随着玻璃纤维含量的增加而明显减小,而同一复合材料的线膨胀系数随温度的升高而逐步增大;在氮气气氛下,随玻璃纤维含量的增加,竹粉/HDPE复合材料的摩擦系数先逐渐增大,而后基本保持不变,磨损率逐渐减小。所得结论显示玻璃纤维含量为3wt%~7wt%的木塑产品适用于建筑横梁(如凉亭或桥梁等),而玻璃纤维含量为7wt%~10wt%的木塑产品适用于高人流量场所(如公园或休闲绿道等)的地面铺装。      

不同改性剂对PP/木粉复合材料性能的影响

研究了苯甲酸(BA)、硬脂酸(SA)、甲苯-2,4-二异氰酸酯(TDI)对聚丙烯/木粉复合材料的改性效果。结果表明,木粉经改性剂处理后,表面极性减弱,与聚丙烯的界面张力降低,相容性提高;所有改性剂均可提高复合材料的拉伸强度、冲击强度以及熔体流动性能,但对弯曲强度影响不大。用TDI/SA复合处理木粉,复合材料的综合性能最好。扫描电镜(SEM)分析表明,木粉经过处理后,木粉与聚丙烯间界面较模糊。     

硅烷偶联剂改性的木粉/P34HB复合包装材料的制备

目的研究硅烷偶联剂KH550含量对木粉/P34HB复合包装材料性能的影响。采用KH550改性木粉,提高与聚(3-羟基丁酸酯-4-羟基丁酸酯)(P34HB)的结合强度,改善复合材料的力学性能和界面相容性。方法以KH550为改性剂,木粉和P34HB为原料,利用共混热压工艺制备改性木粉/P34HB复合材料;通过对复合材料的形貌进行观察,以及傅里叶变换红外光谱(FTIR)、热重分析(TGA)和力学性能分析,研究KH550质量分数不同时对复合材料界面相容性、力学性能和热性能的影响。结果添加KH550后,复合材料的的界面相容性得到改善;FTIR分析表明,KH550已经成功接枝到木粉中;适量的KH550提高了复合材料的热稳定性;复合材料的储能模量增加;复合材料的力学性能也有所提高。此外还得到了最佳的KH550添加量,即质量分数为0.5%。结论 KH550不仅使得木粉与P34HB的相容性得到改善,同时也增强了复合包装材料的力学性能和热性能。     

Date palm wood flour/glass fibre reinforced hybrid composites of recycled polypropylene: Mechanical and thermal properties

Recycled polypropylene (RPP) based hybrid composites of date palm wood flour/glass fibre were prepared by different weight ratios of the two reinforcements. Mixing process was carried out in an extruder and samples were prepared by injection molding machine. Recycled PP properties were improved by reinforcing it by wood flour. The tensile strength and Young’s modulus of wood flour reinforced RPP increased further by adding glass fibre. Glass fibre reinforced composites showed higher hardness than other composites. Morphological studies indicated that glass fiber has good adhesion with recycled PP supporting the improvement of the mechanical properties of hybrid composites with glass fiber addition. Addition of as little 5 wt% glass fibre to wood flour reinforced RPP increases the tensile strength by about 18% relative to the wood flour reinforcement alone. An increase in wood particle content in the PP resulted in a decrease in the degree of crystallinity of the polymer. The tensile strength of the composites increased with an increase in the percentage of crystallinity when adding the glass fibre. The improvement in the mechanical properties with the increase in crystallinity percentage (and with the decrease of the lamellar thicknesses) can be attributed to the constrained region between the lamellae because the agglomeration is absent in this case.     

A comparative study on the effects of Coriolus versicolor on properties of HDPE/wood flour/paper sludge composites

In this study, the effects of white-rot fungus (Coriolus versicolor) on the properties of high density polyethylene (HDPE)/wood flour/paper sludge composites were examined. In addition, the effectiveness of using coupling agent on the durability of decayed and undecayed WPCs was investigated. Two different types of sludge materials, namely paper making waste water sludge (PS) and ink-eliminated sludge (IES) were used. The mechanical properties, morphology, and water absorption of fabricated composites were investigated. At a similar wood flour loading, except for modulus of elasticity, the fungi treated composites showed lower mechanical properties (such as modulus of rupture and unnotched Izod impact strength), and higher water absorption compared to untreated composites. According to the results, addition of wood flour decreased the resistance of the composites to moisture and fungal environment. The exposure of the composites to a 4-cycle (2, 24, 48 and 72 h) water immersion caused serious damage to the interfacial adhesion between wood flour and polymer matrix due to contraction and swelling stresses developed during the cyclic exposure. The detrimental effect of fungal treatment on the water uptake of the composites could be explained by the degradation of lignin which made the cellulose content more accessible. Further, it makes chains of cavities that accelerate water absorption. However, the weight losses of all cases of treated composites were low (less than 2.5%), while PS filled composites were more susceptible to white-rot fungi. The addition of coupling agent during the compounding of wood flour and HDPE prevented the colonization and proliferation of fungus on the surface of the composites, and had an advantageous effect on the water uptake and mechanical properties of both treated and untreated composites.     

Utilization of olive mill sludge in manufacture of lignocellulosic/polypropylene composite

This study evaluated some physical and mechanical properties of injection-moulded polypropylene (PP) composites reinforced with various mixtures of the wood flour (WF) and the olive mill sludge (OMS). Water resistance of the composites improved by the increasing OMS flour content. However, the flexural properties of the composites decreased with increasing OMS flour content. The addition of a coupling agent improved the compatibility between the lignocellulosic material and PP through esterification and thus reduced the water absorption and improved the stability and mechanical properties. The findings obtained in the study showed that the OMS was capable of serving as new reinforcing filler in the manufacturing of thermoplastic polymer composites.