造纸废渣、废地膜再生处理制备聚合物基废弃物复合材料研究

【作者】 柴希娟；

【导师】 孙可伟；

【作者基本信息】 昆明理工大学 ， 环境工程， 2007， 博士

【摘要】 塑料产业和造纸行业是国民经济的两大支柱，而在塑料和纸业的生产以及消费过程中产生的废地膜、造纸废渣亦是两类重大的污染源。目前，对于这两种污染物的综合利用仍存在能耗过高，二次污染严重等问题。论文针对这些综合利用方式存在的缺陷与不足，研究了适合这两种废弃物的更有效、更环保、产品附加值更高的综合利用新方式，解决了用废弃物制备复合材料的难点，制备了强度产生协同效应的二次纤维和废渣粒子混杂增强废地膜复合材料并探索了更有效的强化复合材料力学性能的新工艺。论文以两大废弃物，废地膜和瓦楞纸业的造纸废渣为主要原料，在对二者进行破碎—清洗和杀菌—湿法筛分等有效的前处理后，采用熔融共混法制备了二次纤维/废地膜、废渣粒子/废地膜以及二次纤维和废渣粒子混杂增强废地膜复合材料等一系列聚合物基废弃物复合材料。试验采用傅立叶红外光谱(FTIR)、衰减全反射光谱(ATR)、差示扫描量热法(DSC)和扫描电镜(SEM)等测试手段对复合材料的微观特性进行了分析表征。试验制备的三种聚合物基废弃物复合材料的力学性能均显著优于废地膜基体材料，可广泛用于防火隔音材料、装璜材料、水泥模板、市政设施、缓冲材料等领域。论文首次对回收植物纤维在聚合物基废弃物复合材料中的应用进行了研究。在二次纤维/废地膜复合材料和废渣粒子/废地膜复合材料的制备中，论文系统研究了制备工艺、二次纤维含量以及废渣粒子粒径和含量对复合材料各种力学性能的影响。研究发现，在二次纤维增强体系中，当成型温度为160℃、成型压力为15MPa、混炼时间为15min、二次纤维的质量分数为20wt％时，二次纤维/废地膜复合材料的综合力学性能最优。此时，复合材料的抗弯强度和抗拉强度分别比聚乙烯基体提高17.27％和16.22％；在废渣粒子增强体系中，当粒子的质量含量不超过30wt％时，粒径分别为63.21μm、106.75μm和214.94μm的废渣粒子对废地膜复合材料均具有一定的增强作用，且增强作用随着粒子粒径和含量的增大而减弱。在研究二次纤维/废地膜复合材料时笔者发现，二次纤维对界面处存在间隙，界面黏结效果较差的复合材料仍具有一定的增强作用。针对这种增强事实，论文对短纤维增强聚合物基复合材料的经典增强机理进行了补充。在得出二次纤维/废地膜复合材料和废渣粒子/废地膜复合材料的最优制备工艺参数的基础上，论文将不同粒径的废渣粒子和二次纤维分别进行配合制备了混杂增强废地膜复合材料。研究了组分配比对混杂增强复合材料力学性能的影响，并将混杂增强复合材料的力学强度同等质量含量下单一废渣粒子和单一二次纤维增强废地膜复合材料进行对比，对比发现，二次纤维和废渣粒子的配合使用使混杂增强复合材料在强度方向上产生了协同效应。试验选用硅烷偶联剂KH550和KH560分别对二次纤维、废渣粒子以及二次纤维和废渣粒子混杂增强体系进行了改性处理。研究结果表明，KH550和KH560对复合材料的改性效果几乎相当，且均可在一定程度上提高复合材料的力学强度；经过改性处理后，三种复合材料体系的热湿尺寸稳定性均得到改善；粒径为106.75μm的混杂增强体系经过KH550改性处理后，所得复合材料的抗弯强度提高约4.05％～10.62％、抗拉强度提高约5.30％～16.69％、抗冲击强度提高约10.41％～21.45％。论文针对硅烷偶联剂改性工艺较为繁琐、改性效果不显著等缺陷，探索了更为简便、有效地强化聚合物基废弃物复合材料力学性能的新工艺。试验在马来酸酐接枝聚乙烯增容的条件下，利用微波辐照技术对二次纤维和废渣粒子混杂增强废地膜复合材料进行了强化处理。研究发现，该强化处理工艺不但更加简捷，而且对复合材料力学强度的强化效果是KH550改性效果的1.58～4.04倍。论文较系统地研究了复合材料制备方法、微波功率和时间以及不同微波辐照方式对复合材料力学性能的影响，并采用ATR、DSC、SEM等微观测试手段分析了微波辐照的强化机理。研究表明，一步法试样的综合力学性能优于两步法；在200w、400w、600w和850w四种微波功率下，当辐照时间不超过240s时，微波辐照强化处理可以显著提高混杂增强复合材料的抗冲击韧性；研究同时发现，微波间断辐照对复合材料的强化效果优于微波连续辐照。笔者认为，微波间断辐照和连续辐照在复合材料内部引起的不同热效应以及复合材料结构的不同变化是导致该结果的主要原因。更多还原

【Abstract】 Plastics and papermaking industry is the two major mainstay of national economy, while waste plastics and papermaking residue formed in process of manufacture and consumption are also two magnitude contamination spots. Overtop energy consumption and serious secondary pollution is the distinct defects existing in the current comprehensive utilization methods of the two wastes. Aiming at those defects, new utilization way is researched in the paper, which solves the bottleneck of the new method and prepare hybrid composite possessing Synergistic effect. New reinforcement way is also explored in the essay.A series of waste composites were produced through melt blending using waste plastics and papermaking residue, which were pretreated by crashing-cleaning and sterilization-wet screening process, individual. Microscope test means such as FTIR, ATR, DSC and SEM are applied in the essay. Further, mechanical performance of the waste composite is generally higher than those of matrix materials, and the former can be used in material field of decoration, cement template and public utilities, etc.The applied research of reclaim plant fiber in polymer matrix waste composite is carried out in the essay firstly. Effect of preparation craftwork, properties of secondary-fiber and waste particle on mechanical performance of the waste composite are investigated. Results indicate that in secondary-fiber reinforced system, the optimal blend temperature, molding pressure, blend time and secondary-fiber mass content are 160°C, 15MPa, 15min and 20wt%, where the flexural and tensile strength of secondary-fiber/waste membrane increase by 17.27% and 16.22% compared to those of waste membrane material; In the particle reinforced composite system, waste particle make well reinforcement role when particle size is 63.21μm、106.75μm and 214.94μm, respectively, and reinforment role will behave more prominent with decreasing of particle size and content when the particle mass content is less than 30%.Author discovers that secondary-fiber has well reinforcement in waste composite, which possesses poor adhesion and gap at the interface. Aiming at the fact, typical strengthening mechanism of polymer matrix composite is complemented.The hybrid composite containing waste particles and secondary-fiber are prepared based on the optimal process parameter of secondary-fiber/waste membrane and waste particle/waste membrane composite. Effect of component match on mechanical strength is studied in the paper. Results show that mechanical properties of hybrid composite are enhanced comparing to the corresponding mechanical strength of secondary-fiber/waste membrane and waste particle/waste membrane composite under the same mass content. And the results show that positive Synergistic effect appears in hybrid composite.In the work, silane coupler KH550 and KH560 chemical surface modification have been performed on the secondary-fiber, waste particle and hybrid reinforced system. Results show that the two silane couplers have the similar modification effect, which can enhance mechanical performance of the three kinds waste composites in certain extend. The dimensional stability of composite in moist heat condition is improved after retreating. Results for mechanical performance indicate that flexural strength, tensile strength and impact strength of hybrid composite are increased by from 4.05% to 10.62%, 5.30% to 16.69%, and 10.41% to 21.45%, respectively after being modificated, when particle size is 106.75um.Because of the poor reinforcement and complex process of silane coupler, new mofication method to improve mechanical properties is quested in the essay. Mechanical performance of hybrid composite is intensified by microwave irradiation with MAPE existing. Research indicates that microwave irradiation technic has more potential comparing to silane coupler pretreatment increasing by 1.58 times to 4.04 times.Effect of different composite preparation method, microwave power, irradiation time and different irradiation way on mechanical performance of hybrid composite is researched in this paper. The intensified mechanism has been analyzed by means of FTIR, ATR, DSC and SEM. Results indicate that the general mechanical properties of composite prepared by one step process is higher than those of composite by two step process; impact strength are enhanced after irradiated by microwave under 200w、400w、600w and 850w microwave power when irradiation time is not exceeding 240 seconds; The general mechanical properties of composite intensified by microwave discontinue irradiation is higher than those intensified by continues irradiation. Author proposes that the different thermal effect and structural variation in inner composite resulted by the two irradiation ways is the root cause for explaining the different intensified effect.更多还原