Effect of Polyamide 66 on the Mechanical and Thermal Properties of Post-Industrial Waste Polyamide 6

Post-industrial waste (PIW) polyamide 6 is successfully used in lieu of commercial virgin polyamide 6, in several automotive applications. The presence of polyamide 66 in the final formulation may affect the mechanical and thermal properties of the PIW polyamide 6 materials. Using unreinforced polyamide 6 from PIW and commercial sources, it was found that the addition of polyamide 66 (below 10 wt.%) lowered the crystallization rate and crystallinity level of all polyamide 6 materials. The thermal and mechanical properties of glass fiber (GF) reinforced PIW polyamide 6 compounds with and without polyamide 66 were also studied. Differential scanning calorimetry (DSC) showed that reinforced materials without polyamide 66 had a higher level of crystallinity. Furthermore, dynamic mechanical analysis (DMA) showed that reinforced compounds without polyamide 66 also had a faster storage modulus buildup immediately after injection molding. Reinforced PIW polyamide 6 compounds without polyamide 66 also exhibited higher tensile and higher vibration weld strengths as well as a thicker heat affected zone (HAZ) than those with polyamide 66, leading to the conclusion that polyamide 66 had a detrimental effect on crystallinity level and consequently on the mechanical properties of GF-reinforced PIW polyamide 6 materials.     

Preliminary experiments on metallisation of ceramic oxide superconductors

Abstract

The present paper briefly reports on preliminary experiments on two new methods for the metallisation of ceramic oxide high temperature superconductors )HTS compounds): sinter-permeate silver and chemically precipitated silver. By using well characterised HTS samples for the measurement of superconducting properties it is shown that successful metallisation and jointing were obtained. The two methods are considered to have potential for further development and application in this field.     

Bone china formulated with waste glass

Abstract

Abstract

Bone china is known for its technical and aesthetical quality with distinguishable whiteness, brightness and high mechanical strength. In this work, the use of waste glass was investigated in a bone china composition. This makes the production of this porcelain even more interesting from the environmental point of view, since most of its raw materials are from recyclable sources. Potash feldspar was partially replaced by waste glass, and the technical and slip rheological properties, phase development and microstructure after firing of the ceramic bodies were evaluated. The results revealed that waste glass provides a reduction in firing temperature and large plateau for firing while maintaining the quality of the final porcelain, including thermal expansion and mechanical strength.     

Recycling Carpet Waste by Injection and Compression Molding

Studies have been carried out to convert carpet waste into valued products. Two common processes, injection and compression molding, can be used to recycle carpet waste. Three types of carpet waste have been recycled: (1) edge trim from carpet manufacturing, (2) polypropylene shear lint from cutting tufted carpet loops, and (3) separated polypropylene from postconsumer carpet waste. For injection molding, shredded carpet waste was debulked, ground, dried, and molded. For compression molding, the recycled carpet waste was combined with glass mat reinforcement. The compression-molding process consists of debulking, stacking with glass mats, and consolidation. The mechanical testing results are encouraging. The injection-molded samples showed properties acceptable for many applications. The glass-mat-reinforced carpet waste made by compression molding had properties comparable to commercial virgin thermoplastics reinforced with glass mat.     

Utilization of Recycled Carpet Waste Fibers for Reinforcement of Concrete and Soil

The use of recycled fibers from textile waste for concrete and soil reinforcement is a very attractive approach, with such benefits as performance enhancement, low-cost raw materials, and reduced needs for landfilling. This article discusses the general advantages of fiber reinforcement and reviews some studies on the use of carpet waste fibers for concrete and soil reinforcement. A study on recycled carpet waste fibers for fiber-reinforced concrete (FRC) showed a significant toughness increase and reduced shrinkage. It included two concrete mix designs and a wide range of fiber dosage rates, from 0.07 to 2.0 vol.%. A research program on fiber-reinforced soil is underway for fiber characterization, analysis of the engineering properties of the fiber-soil systems, and field trials. A significant improvement in soil behavior under the triaxial loading condition was observed.     

Production of Chlorosulfonated Rubber from Postconsumer Polyethylene and Evaluation of Produced Rubber Properties

In order to convert the postconsumer polyethylene to a valuable product, chlorosulfonation of virgin and highly degraded polyethylene has been carried out in the solution phase under atmospheric pressure. Produced chlorosulfonated polyethylene samples from virgin and degraded HDPE are compounded and cured at different temperatures and their mechanical properties are determined. The results show that degradation of used polyethylene does not have noticeable negative effects on the final mechanical properties of produced chlorosulfonated rubbers. Therefore, it can be concluded that chlorosulfonation can be considered as an effective new method for polyolefin recycling.     

Preparation of spinel LiMn2O4 cathode material from used zinc-carbon and lithium-ion batteries

Due to the progressive shortage of primary resources and growing environmental concerns over industrial and household residues, proper management of electronic wastes is of great importance in addressing sustainability issues. Spent batteries are considered as important secondary sources of their constituting components. In this study, the co-recycling of used zinc-carbon and lithium-ion batteries was performed aiming at the recovery of their manganese and lithium contents as compounds which can be used as precursors for the synthesis of spinel LiMn₂O₄. Manganese was recovered in the form of amorphous, submicron, spherical nodules of MnO₂ after acid leaching of zinc-carbon battery pastes. Lithium was obtained from nickel-manganese-cobalt (NMC) batteries as its monohydrate oxalate (C₂HLiO₄.H₂O) through selective leaching in oxalic acid followed by crystallization. Lithium carbonate was also prepared by subsequent calcination of the oxalate. The synthesis of LiMn₂O₄ spinel cathode was investigated using the reclaimed Li- and Mn-containing compounds via solid-state synthesis method. The effect of such parameters as type of precursors (C₂HLiO₄.H₂O/Li₂CO₃ with Mn₂O₃/MnO₂), temperature (750, 800, and 850 °C), and time (8 and 10 h) on the synthesis of LiMn₂O₄ was investigated. The products were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The crystallographic parameters from XRD analysis were used to predict the electrochemical behavior of the synthesized cathode materials. Based on these, the spinel powder synthesized at 850°C?10h from Li₂CO₃?Mn₂O₃ starting mixture was determined as the cathode material with the best electrochemical properties among the synthesized samples. The galvanostatic charge/discharge evaluation within the voltage range of 2.5–4.3 V showed the specific capacity of the 850°C-10 h sample to be 127.87 mAhg^?1.     

玻璃纤维毡增强热塑性复合材料废弃制品回收利用技术的研究

对废弃玻璃纤维毡增强热塑性复合材料（ＧＭＴ）制品回收利用技术进行了研究,针对制品的特点,研究了回炉预热升温过程,提出了较为合理的升温序列,使弃弃制品得到完全回收利用;探索了回收利用的次数对制品弯曲性能的影响,经过９次回炉加工的废弃制品的性能仍满足使用要求。     

废旧PVC塑料的回收利用

本文综述了废旧聚氯乙烯（PVC）的资源化利用和存在的问题;介绍了几种回收废IEIPVC（聚氯乙烯）的工艺,包括溶剂法、机械法、化学法及焚烧法,介绍了当前PVC的回收利用及其对环境影响的研究进展,并对PVC未来的应用及其回收利用进行了一些思考。     

Properties of natural rubber vulcanizates containing mechanochemically devulcanized ground tire rubber

The devulcanization of ground tire rubber (GTR) was carried out with a self-designed pan-mill type mechanochemical reactor. Gel fraction and crosslink density measurements confirmed the occurrence of stress induced mechanochemical devulcanization of GTR. The partially devulcanized GTR (dGTR) was blended with virgin natural rubber (NR) at different ratios. The curing characteristics and mechanical properties of these composites were investigated and compared with those composites of raw ground tire rubber (rGTR) and NR. The results showed that the tensile properties of the dGTR/NR vulcanizates were much better than those of the rGTR/NR vulcanizates, which are comparable to or even better than the virgin vulcanizate, indicating the significant benefit of mechanochemical devulcanization. At the GTR content of 10%, the tensile strength of the dGTR/NR blends increased to 23.2 MPa from 13.7 MPa of the rGTR/NR blends, enhanced by 69% through partial devulcanization of GTR, and the elongation at break increased by 47%.