【作者】 龚丽；

【导师】 王清文；

【作者基本信息】 东北林业大学 ， 生物材料工程， 2011， 硕士

【摘要】 回收的聚酯主要用于制备共混塑料合金和熔融纺丝成聚酯短纤维,生成的聚酯短纤维由于性能较差,不适合用于纺织业,一般用作填料。本文采用聚对苯二甲酸乙二酯(PET)短纤维增强高密度聚乙烯(HDPE)/木粉复合材料,研究PET纤维添加量对HDPE/木粉复合材料性能的影响,并采用不同浓度的NaOH和γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH570)溶液对PET纤维表面进行改性,通过扫描电镜(SEM)和傅里叶红外光谱图(FT-IR)表征改性后的PET纤维。采用静态力学、动态力学、吸水率测试和SEM等方法考察PET纤维用量、分布形态及其改性对HDPE/木粉复合材料性能的影响,优选出PET纤维的最佳添加量和改性PET纤维的最佳方法和工艺条件。与未添加PET纤维的HDPE/木粉复合材料相比,添加PET纤维能提高HDPE/木粉复合材料的力学性能和耐水性,PET纤维的最佳添加量为3%左右,如PET纤维添加量过高,PET纤维分散不均匀,团聚现象明显,导致HDPE/木粉复合材料的强度和耐水性均下降；HDPE接枝马来酸酐(MA)、NaOH和KH570处理PET纤维,均能提高HDPE/木粉复合材料的力学性能,HDPE接枝MA和NaOH溶液处理PET纤维制备的HDPE/木粉复合材料的性能最佳,但NaOH溶液处理PET纤维会导致HDPE/木粉复合材料的耐水性下降,NaOH溶液浓度过高,HDPE/木粉复合材料的力学性能也会下降。回收聚酯通过熔融纺丝制成聚酯短纤维增强木塑能一定程度的提高复合材料的性能,但聚酯的熔融纺丝工艺较复杂,为了简化回收聚酯应用于木塑复合材料制备的工艺条件,本文还探索了回收PET(rPET)树脂本体改性及其改性后制备聚酯/木粉复合材料的加工方法。将rPET与马来酸酐接枝的聚乙烯(MAPE)共混,并添加钛酸酯(Ti(OBu)4)催化剂促进rPET与MAPE间的反应,提高其相容性,研究了Ti(OBu)4催化剂对rPET/MAPE共混物性能的影响。然后采用不同的加工方法和工艺条件将改性后的rPET与木粉混合制备成聚酯/木粉复合材料,得出有利于聚酯/木粉复合材料制备的成型方法和成型工艺条件。流变研究表明rPET/MAPE共混物的粘度随着剪切速率的提高而迅速下降,表现为剪切变稀行为；由于rPET/MAPE共混物呈两相界面,PET与MAPE没有完全相容,rPET/MAPE共混物的力学性能不高,添加Ti(OBu)4能提高PET与MAPE的相容性,进一步提高其力学性能和低剪切作用下的粘度,同时也会导致PET自身部分降解,所以当Ti(OBu)4的含量大于0.1%时,rPET/MAPE共混物的力学性能和粘度都会有所下降,且Ti(OBu)4的添加并没有降低PET的熔点。采用热压成型法将添加0.1%的Ti(OBu)4改性的rPET/MAPE共混物与木粉混合制备聚酯/木粉复合材料,所得的复合材料力学性能较低；单螺杆成型需要木粉在高温下长时间受热,木粉会碳化,所以无法采用单螺杆成型制备聚酯/木粉复合材料。更多还原

【Abstract】 Recycled polyester is widely used for preparation of plasitic alloys by melt extrusion and processing fiber by melt-spinning. Polyester fiber is not proper to use in textile indutry due to poor properties. The short fibers are therefore used as filler in the composites. This work studies the effects of the content of polyethylene terephthalate(PET) fiber on the properties of resulting wood flour/HDPE composites(PF-WPC). The PET fibers were treated with alkaline orγ-methacryloxypropyl trimethoxy silane (KH570) and then characterized using the scanning electron microscope (SEM) and Fourier transform infrared spectrum (FT-IR). The effects of content of PET. distribution of PET, surface treatments of PET on the properties of the PF reinforced WPC were investigated. The optimized processing parameters were determined accordingly.Compared to unreinforced WPC, the mechanical properties and water resistance of PF-WPC were improved. The optimum PET conetent was about 3%, over which the strength and water resistance of PF-WPC decreased due to uneven dispersion and agglomeration of PET fiber. Either grafting maleic anhydride (MA) onto HDPE or surface treating PET fiber with NaOH and KH570 can improve the properties of the resulting PF-WPC. Treatment of PET fiber with NaOH caused an increase in water uptake and a reduction in the mechanical properties of the resulting PF-WPC.Recycled polyethylene terephthalate (rPET) was modified through melt compounding with MAPE in the presence of titanium tetrabutoxide (Ti(OBu)4) as transesterification catalyst. The effect of the content of Ti(OBu)4 on the properties of rPET/MAPE was investigated. To obtain molding method and processing conditions for wood/rPET composites, modified rPET melt compounded with wood flour to prepare polyester/wood flour composites in diffirent processing methods.Rheologic study indicated that the viscosity of rPET/MAPE was rapidly decreased with increase of frequency, showing a shear thinning behavior. The mechanical properties of rPET/MAPE blend was weak due to the two-phase interface between rPET and MAPE as observed by SEM. The addition of Ti(OBu)4 increased the mechanical properties and viscosity of rPET/MAPE, which attributed to the effective improvement of interfacial compatibility between rPET and MAPE. As the amount of Ti(OBu)4 exceeded 1%, the mechanical properties and viscosity of rPET/MAPE decreased, which may be due to PET degradation at high temperature. Addition of Ti(OBu)4 didn’t decrease melt point of PET. The mechanical properties of polyester/wood flour composites contained modified rPET and wood flour by compression molding were poor. The single-screw extrusion wasn’t appropriate for preparation of polyester/wood flour composites due to wood degradation in the extrudsion chamber.更多还原