【作者】 王道登；

【导师】 孙建中；

【作者基本信息】 浙江大学 ， 化学工程， 2007， 硕士

【摘要】 本文以线性低密度聚乙烯（LLDPE）/乙烯辛烯共聚物（POE）/CaCO₃体系,经共混造粒、挤出流延和单轴拉伸致孔制备微孔膜。考察了体系流变特性及影响因素。研究了工艺条件如拉伸倍数及体系组成对微孔膜的微孔形态及防水透湿性能的影响。对微孔的结构形态、微孔孔径、孔径分布及空隙率进行了测试表征。对微孔膜的防水透湿性能进行了模拟研究。在此基础上,在工业装置上进行了防水透湿三层复合膜（内外两层为丙纶无纺布、中间层为防水透湿微孔膜）的无粘合剂连续点热压复合的试验,研究了工艺条件对点热压复合效果及复合膜的防水透湿性能的影响。对LLDPE/POE/CaCO₃/竹质活性碳微孔膜进行了初步研究。LLDPE/POE/CaCO₃体系的熔体流变特性研究表明,体系为假塑性流体。CaCO₃含量越少,假塑性越强。POE含量为树脂总量的1/4时,体系的假塑性最强。加入POE后,在一定温度和剪切速率范围内,熔体的表观粘度下降,流动性得以改善,有利于挤出流延。拉伸倍数和填料用量等工艺条件对LLDPE/POE/CaCO₃防水透湿微孔膜孔隙结构和防水透湿性能影响的研究表明,填充有CaCO₃的LLDPE/POE挤出流延膜经拉伸后,在CaCO₃与树脂的相界面出现“脱胶”现象,形成裂缝状的微孔。制备的微孔膜随拉伸倍率的提高,孔径增加,空隙率上升。CaCO₃用量约100份（相对于100份树脂）时,微孔膜的空隙率最大,有利于提高微孔膜的透湿性能。LLDPE/POE/CaCO₃微孔膜透湿性能的模拟研究表明,该微孔膜的透湿属于Fickian扩散类型。模拟计算表明,使透湿通量增加的主要因素是单位膜面积的微孔数量,增大微孔孔径并不能使透湿通量增加。点热压复合型防水透湿复合膜的研究表明,热压复合的温度、压力及POE用量对复合膜的层间粘结牢度及防水透湿性能均有显著影响。温度以90℃左右为宜,温度过低时,层间粘结牢度达不到多层复合膜粘结强度的要求。温度过高,则微孔膜在经受热压辊表面特制突起构造的点压合时易使微孔膜局部损伤,从而使防水性能能达不到要求。热压复合的压力以15 MPa左右为宜,压力过低时,层间粘结牢度差,压力过高则损伤微孔膜,使防水性能显著下降。POE用量以占树脂总量的25%为宜,POE用量过低（＜15%）时,即使温度和压力在合适的范围内,复合膜的层间粘结强度也不能满足要求。POE用量过高（＞30%）时,因易引起微孔膜的热压损伤,而使复合膜的防水性能不佳。LLDPE/POE/CaCO₃/竹质活性碳微孔膜的初步研究表明,在LLDPE/POE/CaCO₃体系中加入竹质活性碳后,体系的拉伸致孔性变差,但在拉伸倍数为4时仍可制备微孔膜。更多还原

【Abstract】 A waterproof and moisture permeable microporous film was prepared from liner low density polyethylene（LLDPE）/ethylene-octene copolymer（POE）/ CaCO₃ system via blend granulation, tape extrusion, driveling ,and uniaxial stretch. The rheological performance and its influencing factors of the system were investigated. Effects of operating conditions, such as stretch ratio, system components on the micropore morphology, waterproof, and moisture permeability of the microporous film were studied experimentally. The structure morphology, micropore size and distribution, and porosity of the microporous film were measured. The properties of waterproof and moisture permeability of the microporous film were simulated. On the basis of microporous film, preparation of a 3-laminate sheeting of PP nonwoven fabric/microporous film/PP nonwoven fabric was carried out using the point hot -pressed composition method at an industrial installation. Effects of technological conditions of hot-pressed composition process on the composition strength, the watertightnees, and moisture permeability were investigated. The preparation of a miacroporous film of LLDPE/POE/ CaCO₃/bamboo charcoal activated carbon was studied preliminarily.The study of the rheological performance of LLDPE/POE/ CaCO₃ system shows that the system is a pseudoplastic fluid. The results indicate that the less the CaCO₃ content, the more pseudoplastic, and that the pseudo-plasticity is more strong while the POE content is 25% in total amount of resin. The results show also that in proper range of temperature and shear rate the apparent viscosity decreases and the mobility is improved due to using of POE.The study of effects of the stretch ratio and technological conditions on the morphology, the watertightness, and the moisture permeability of the microporous film of LLDPE/POE/ CaCO₃ shows that after stretching of the CaCO₃-filled LLDPE/POE film the interface of CaCO₃ and resin occurs debonding to form microporous cracks, and that the pore size and porosity of the microporous film increase with increase of the stretch ratio. The results show also that the porosity of the microporous film is the biggest while the amount of is 100 shares（correspond to 100 shares of resin） , which is beneficial to the moisture permeability of the microporous film.The simulation of the moisture permeability of LLDPE/POE/ CaCO₃ microporous film indicates that the moisture permeability of the microporous film belongs to fickian diffusion. The simulation results show also that the main factor of the increase of moisture permeability is the pore number per unit area of the film, and that the moisture permeability can not be increased by increasing the pore size.The study of the multilaminate sheeting with waterproof and moisture permeability composited via point hot-pressed method indicates that effects of composition temperature, pressure, and POE content on the bonding strength, watertightnees, and moisture permeability are significant. The proper temperature is 85～95℃. The bonding strength between layers is poor while the temperature of roller is too low. At high temperature of roller, the microporous film will be injured partially by the protrusile structures at the surface of the hot roller in hot composition process, which makes the waterproof poor. The proper pressure of hot roller is about 15MPa. Lower pressure of hot roller makes the bonding strength poor. Higher pressure of hot roller makes the microporous film injured, which can lead to poor waterproof property. The proper content of POE is 25% in total amount of resin. Lower content of POE（< 20%） makes the bonding strength of laminate sheeting unsatisfactory although the temperature and pressure of hot roller are proper. Higher content of POE（30%） makes the waterproof property poor due to the microporous film’s injury caused by the hot roller.The preliminary study of microporous film of LLDPE/POE/ CaCO₃/bamboo charcoal activated carbon indicates that the waterproof and moisture permeable performance has little change after adding the bamboo charcoal activated carbon. The introduction of the bamboo charcoal activated carbon supplies a basis for preparing a waterproof and breathable film with adsorption function.更多还原