废聚丙烯塑料的回收利用技术

介绍了废聚丙烯塑料能源化的方法(焚烧、无氧及有氧条件下的热分解)与资源化回收利用技术(简单再利用、改性再生利用),并对国内外相关方面的研究和应用情况进行了报道。     

专利资讯

专利名称：玻纤增强聚丙烯塑料废料改性制作中空板原料的生产工艺 本发明涉及一种玻纤增强聚丙烯塑料废料改性应用于中空板的工艺，特征是将玻纤增强聚丙烯废料经烘箱剥离预处理；人工剥离面料，将纯的玻纤增强聚丙烯废料经粉碎，通过双螺杆挤出机挤出为玻纤增强聚丙烯塑料粒；取玻纤增强聚丙烯塑料粒、聚乙烯、阻燃剂、偶联剂和助剂共混，通过双螺杆挤出机挤出为改性混合塑料粒。     

再生骨料及再生混凝土的改性研究

全面综述了再生骨料和再生混凝土改性的试验方法、试验条件和改性效果.     

废旧塑料的再生及其在制管行业中的应用

总结了再生、降解、焚烧及填埋等几种废旧塑料处置方式的特点,指出对于品种单一、老化程度低的废旧塑料应优先选择再生利用.重点介绍了废旧聚氯乙烯塑料、聚乙烯塑料、聚丙烯塑料、氯化聚氯乙烯塑料的再生及其在制管行业中的利用情况进展.     

再生聚丙烯增韧改性研究

对回收聚丙烯(RPP)进行增韧改性,制备回收聚丙烯/回收胶粉(RPP/WRP)和回收聚丙烯/热塑性弹性体POE(RPP/POE)共混材料,研究两种共混材料的韧性、力学、热、流变性能和形态.结果表明,RPP/WRP改性体系有较好的韧性和耐热性,较高的硬度,属于假塑性流体,回收胶粉可以部分替代POE作为某些制品的增韧剂.     

废旧聚丙烯回收利用技术的现状及发展趋势

详细综述了国内外废旧聚丙烯再生利用技术,并对未来废旧聚丙烯回收利用技术的发展趋势进行了预测.     

改性聚丙烯生物填料的制备与应用

对传统聚丙烯生物填料（简称普通填料）进行改性，考察了改性聚丙烯生物填料（简称改性填料）用于模拟废水生物处理的效果。实验结果表明，改性填料比普通填料具有更高的废水处理效率和更大的挂膜量，并能承受更高的气液比（体积比）及气流和水流的冲击。将模拟废水的COD（500mg／L）完全去除，用改性填料时需10.5h，而用普通填料时则需22．5h；在连续运行模式下，改性填料在气液比为40：1时可使废水COD的去除率最高（99％），而普通填料则在气液比为30：1时可使废水COD的去除率最高（79％）。     

改性橙皮静态吸附模拟废水中的Pb2+

采用异丙醇溶液改性橙皮,考察了模拟废水中初始Pb2+质量浓度、废水pH、改性橙皮加入量和吸附时间等因素对改性橙皮对模拟废水中的Pb2+吸附效果的影响。实验结果表明,在初始Pb2+质量浓度为20 mg/L、废水pH为4、改性橙皮加入量为8 g/L、吸附时间为80 min的条件下,改性橙皮对废水中Pb2+的去除率可达88.41%。经浓度为0.1 mol/L的HCl溶液再生后,改性橙皮再生循环使用4次时效果仍较好。改性橙皮对Pb2+的吸附动力学可用准二级动力学方程很好地描述。改性橙皮对Pb2+的吸附符合Langmuir等温吸附方程,表明改性橙皮对Pb2+的吸附以单分子层吸附为主。     

废旧聚乙烯的再生处理技术

从废旧聚乙烯的直接再生、改性再生和裂解再生三个方面,讨论了国内外处理和再生利用的情况,并对其再生技术与应用做了比较.我国处理和回收利用废旧聚乙烯时,要加强生物降解塑料等环境无负荷材料的研究与开发;加强固体废弃物的管理与循环利用的立法;实现经济与环境的和谐发展.     

回收废旧电池外壳聚丙烯的力学和耐热性能研究

社会经济的发展和生活水平的提高使得汽车保有量逐年增加,服役后报废汽车产生的废旧蓄电池也快速上升,报废的蓄电池给环境带来巨大压力。废旧电池外壳是聚丙烯,如何循环利用成为亟待解决问题。采用高抗冲共聚聚丙烯对其进行增韧改性,结果表明:当添加20%共聚聚丙烯后,缺口冲击强度提升39.2%,熔体流动速率降低了48.3%,在150℃进行热老化,300 h后表面没有明显变化,综合性能达到蓄电池专用料水平,同时为回收废旧蓄电池外壳聚丙烯材料的闭环回收提供了可行方案。     

Rheological, Mechanical and Thermal Behaviour of Wood Polymer Composites Based on Recycled Polypropylene

The aim of this paper was to investigate the effect of recycled polypropylene (PP) on the rheological, mechanical and thermal properties of wood flour polypropylene composites. Beforehand, the influence of wood flour treated with a coupling agent on the rheological behaviour had been looked at. By analysing moduli and viscosity curves and studying the thermal and mechanical properties of samples with 10% filler it was possible to see that the recycled PP that was added change in either its physical properties or its rheology. In the other wood plastic composites (WPC) studied, slight changes in the rheology behaviour were observed. However, the same processing parameters may be used with and without recycled PP. Recycled PP is appropriate for these kinds of composites to maintain the optimal rheological properties that make it easier to process the material by extrusion. Furthermore, it is also possible to maintain the thermal and mechanical properties in comparison with the behaviour of virgin PP/wood flour composites.     

Modification of mechanical properties of recycled polypropylene from post-consumer containers

This study is conducted to look at the modification of mechanical properties of recycled polypropylene (PP) from post-consumer containers with the addition of stabilizers, elastomer (ethylene-octene rubber, EOR) and calcium carbonate (CaCO(3)). The mechanical and thermal properties of the blends were evaluated. The results showed limited changes with the addition of elastomer and calcium carbonate on the mechanical properties of the recycled polypropylene. Some differences were observed, but the trends were not reproducible over the different compositions. DSC analysis confirmed the presence of polyethylene (PE) in the recycled polypropylene. The polyethylene impurity and the presence of many different qualities of polypropylene in the recycled material may have prevented any possible improvement in the mechanical properties by the addition of EOR and CaCO(3), improvements seen in previous studies on virgin polypropylene. The compatibility of the different homopolymers and copolymers of PP used in consumer packaging is not known, while polyethylene and polypropylene are known not to be miscible with each other. The mixture of qualities and materials may explain such a poor blending. Reusing and upgrading of recycled PP from post-consumer containers would therefore first require a better sorting of the post-consumer waste. The use of an adequate compatibilizer that would allow a uniform and homogeneous blending of the raw material mixture might enhance the mechanical properties.     

Characteristics of wood–fiber plastic composites made of recycled materials

This study investigates the feasibility of using recycled high density polyethylene (rHDPE), polypropylene (rPP) and old newspaper (rONP) fiber to manufacture experimental composite panels. The panels were made through air-forming and hot press. The effects of the fiber and coupling agent concentration on tensile, flexural, internal bond properties and water absorption and thickness swelling of wood–fiber plastic composites were studied. The use of maleated polypropylene as coupling agent improved the compatibility between the fiber and both plastic matrices and mechanical properties of the resultant composites compared well with those of non-coupled ones. Based on the findings in this work, it appears that recycled materials can be used to manufacture value-added panels without having any significant adverse influence on board properties. It was also found that composites with rHDPE provided moderately superior properties, compared with rPP samples.     

Wood Polypropylene (PP) Composites Manufactured by Mango Wood Waste with Virgin or Recycled PP: Mechanical,Morphology, Melt Flow Index and Crystalline Behaviour

Compositions of wood-polypropylene composites (WPCs) are prepared through melt compounding followed by injection moulding. WPCs are formulated for eight compositions with a different weight ratio of wood, virgin or recycled polypropylene and coupling agent. WPCs compositions are compared in terms of Melt Flow Index, Tensile, FESEM images, Flexural and crystallinity index for same operating variable conditions. From the results, recycled polypropylene based WPCs are superior in comparison to virgin polypropylene based WPCs. With the addition of 5 % coupling agent in recycled polypropylene-based composites for 45:50 composition, tensile and flexural values of WPCs are higher in comparison to all composition and neat virgin or recycled polypropylene. This work stands for the utilization of waste wood with recycled plastic for replacement of wood and virgin plastic.     

Use of recycled plastics in wood plastic composites – A review

The use of recycled and waste thermoplastics has been recently considered for producing wood plastic composites (WPCs). They have great potential for WPCs manufacturing according to results of some limited researches. This paper presents a detailed review about some essential properties of waste and recycled plastics, important for WPCs production, and of research published on the effect of recycled plastics on the physical and mechanical properties of WPCs.     

Use of rubble from building demolition in mortars

Because of increasing waste production and public concerns about the environment, it is desirable to recycle materials from building demolition. If suitably selected, ground, cleaned and sieved in appropriate industrial crushing plants, these materials can be profitably used in concrete. Nevertheless, the presence of masonry instead of concrete rubble is particularly detrimental to the mechanical performance and durability of recycled-aggregate concrete and the same negative effect is detectable when natural sand is replaced by fine recycled aggregate fraction. An alternative use of both masonry rubble and fine recycled material fraction could be in mortars. These could contain either recycled instead of natural sand or powder obtained by bricks crushing as partial cement substitution. In particular, attention is focused on the modification that takes place when either polypropylene or stainless steel fibers are added to these mortars. Polypropylene fibers are added in order to reduce shrinkage of mortars, stainless steel fibers for improving their flexural strength. The combined use of polypropylene fibers and fine recycled material from building demolition could allow the preparation of mortars showing good performance, in particular when coupled with bricks. Furthermore, the combined use of stainless steel fibers and mortars containing brick powder seems to be an effective way to guarantee a high flexural strength.     

Recycled Natural Fiber Polypropylene Composites: Water Absorption/Desorption Kinetics and Dimensional Stability

Detailed analysis of the effects of recycling process on long-term water absorption, thickness swelling and water desorption behavior of natural fiber polypropylene composites is reported. Composite materials containing polypropylene and wood flour, rice hulls or bagasse fibers were produced at constant fiber loading and were exposed to a simulated recycling process consisting of up to five times grinding and reprocessing under controlled conditions. A wide range of analytical methods including water absorption/desorption tests, thickness swelling tests, density measurement, scanning electron microscopy, image analysis, contact angle, fiber length analysis and Fourier transform infrared spectroscopy was employed to understand the hygroscopic behavior of the recycled composites. Water absorption and thickness swelling behaviors were modeled using existing predictive models. Results indicated that generally the recycled composites had considerably lower water absorption and thickness swellings as compared with the original composites which were attributed to changes in physical and chemical properties of the composites induced by the recycling process.     

Molecular Modification and Compatibilization of Collected Polyethylene

The increasing use of plastics in packaging materials leads to growing amounts of plastic waste. Recycling material is generally regarded as advantageous. But in fact very few products are made from plastic waste, partly this can be explained by that little is known about the recycling process and the properties of collected materials. There is a need for injection moulding grades of recycled polyethylene, while large amounts of extrusion grades are available from packaging waste. A controlled way of de-branching or partly degrading PE would be desirable. Peroxides are commonly used to crosslink polyolefins, but under certain conditions a chain scission reaction occur. Another problem encountered with recycling of polyethylene are the poor miscibility of low amounts contaminations, i. e. polypropylene. A compatibilizer can improve properties of such polymer blends, in this work EPDM is used as compatibilzer. Studies of mechanical properties and viscosity measurements show that it is possible to partly degrade PE with peroxide exposing it to high temperature and oxygen. The properties of PE/PP blends were improved with EPDM as compatibilizer.     

Recycled blocks with improved sound and fire insulation containing construction and demolition waste

The environmental problem posed by construction and demolition waste (C&D waste) is derived not only from the high volume produced, but also from its treatment and disposal. Treatment plants receive C&D waste which is then transformed into a recycled mixed aggregate. The byproduct is mainly used for low-value-added applications such as land escape restoration, despite the high quality of the aggregate. In the present work, the chemical composition properties and grading curve properties of these aggregates are defined. Furthermore, the resulting recycled concrete with a high proportion of recycled composition, from 20% to 100% replacement of fine and coarse aggregate, is characterized physically and mechanically. An environmental study of the new construction material when all aggregates are substituted by C&D waste shows a low toxicity level, similar to that of other construction materials. The new material also has improved properties with respect to standard concrete such as high fire resistance, good heat insulation, and acoustic insulation.