Selective thermal recycling for graphene growth on natural substrates: A comparative study on life cycle assessment,energy consumption,and mechanical performance in recompounding

Manufacturing of carbon-based materials from waste thermoplastics is a keystone to reduce adverse environmental impacts. There are numerous attempts for sustainable graphene manufacturing from various waste sources by thermal treatment but there is no clear distinction on the effective conversion process by addressing reliable CO₂ footprints. This study provides a comprehensive benchmarking study on the conversion of waste polypropylene plastics coming from yogurt containers into graphene on the substrate of talc by applying two upcycling techniques of catalytic carbonization (CC) and flash pyrolysis (FP) by comparing energy and speed of the processes and a dimensional stability and physical characteristics of the produced graphene substances by adopting a comparative life cycle assessment. FP led to the sphericalization of graphenes due to fast dehydration, cross-linking, and carbonization of aromatic structures. On the other hand, gradual heating in CC caused the formation of tubular-like graphene structures. In addition, FP became advantageous by resulting in 52% of CO₂ emission compared with CC process. On the other hand, graphenes separated from talcs exhibited a remarkable 70% reduction in global warming potential compared with conventional graphene production from graphite. In order to complete the value chain and circularity, the mechanical performance of two different hybrid additives produced by selective thermal recycling in recompounding with copolymer polypropylene was examined, and additives from CC enhanced the flexural and tensile properties two times better than the one from FP. With this study, it becomes possible to compare analysis of graphene growth on natural substrates by exploring life cycle assessment, energy consumption, and mechanical performance with selective thermal recycling and recompounding.     

滑石粉对中华M2方向盘护盖用聚丙烯专用料性能的影响

本文探讨了滑石粉对聚丙烯专用料性能的影响等,并根据中华M2方向盘护盖的使用要求,选择了最佳的专用料配方。     

Structure and properties of highly filled poly (vinyl alcohol)/talc composites prepared through thermal processing: effects of talc size

Poly (vinyl alcohol) (PVA), a multi-hydroxyl polymer with excellent comprehensive properties, is an expected candidate to prepare high-performance polymer-based composites without using any coupling agents or compatibilisers. However, the poor thermal processability of PVA is its biggest obstacle. In this paper, by adopting polyol as a plasticiser, highly filled PVA/talc composites with good mechanical properties were successfully obtained through melt extrusion and injection, and the effects of talc size on structure and properties of the composites were studied. The results showed that talc highly filled PVA composites had satisfying melt processability, and the decrease of talc particle size increased the –OH groups on the edges of the talc layers, thus improving the compatibility between talc and PVA, and making talc particles dispersed more uniformly in PVA matrix. As a result, the composites with smaller talc particles had the higher threshold filler concentration to form the filler networks and the better flow behaviour. The smaller talc flakes also exhibited higher orientation in PVA matrix and induced more PVA molecular chains to orient along the melt flow direction, leading to the enhancement of the mechanical properties of the composites.     

粘合剂对层间加填纸张性能的影响

实验选用滑石粉和碳酸钙为矿物填料,聚乙烯醇、苯丙乳液以及两种取代度不同的阳离子淀粉作为层间加填的粘合剂,研究了瓦楞原纸成形过程中,粘合剂与填料对成纸物理强度性能的影响。结果表明:采用聚乙烯醇及苯丙乳液作为粘合剂的效果优于两种取代度不同的阳离子淀粉,而低取代度的阳离子淀粉又优于高取代度阳离子淀粉。同时,以碳酸钙作为填料,苯丙乳液作为粘合剂进行层间加填时,采用全废纸抄造瓦楞原纸,其成纸物理强度性能优于滑石粉。且当碳酸钙用量为25%(对绝干浆),苯丙乳液用量为2%时,瓦楞原纸的抗张强度与浆内加填相比提高了23%,且未出现纸张分层现象,满足使用要求。     

滑石矿手选尾矿选矿试验研究

本试验样品滑石矿手选尾矿主要成分为滑石和菱镁矿,另有少量石英等。试验采用粗磨粗选、二次精选、中矿再磨返粗选的流程,可获得精矿品位滑石含量为95．67％（SiO2含量为61．68％）的高品位精矿粉,滑石回收率为89．43％。对该手选尾矿的回收利用,不仅提高了优质滑石产品的产量,同时使滑石资源得到充分利用。     

造纸用滑石的功能特性及其产品的研发方向

概述了造纸用滑石的主要功能特性和用途.滑石在未来造纸市场的经济技术定位,主要体现在它特有的功能特性方面,高品质滑石主要用于造纸粘性物控制剂和涂料级产品,低档滑石及其复配产品主要用于造纸填料.黑滑石储量丰富,具有潜在的市场前景,开发与此相关的生产制造技术和装备以及相应的应用技术是今后的主要发展方向.     

Probing toughness of polycarbonate (PC: ductile and brittle)/polypropylene (PP) blends and talc-triggered PC/PP brittle composites with diverse impact fracture parameters

Polycarbonates (PCs) are commonly used as a blend and a composite to achieve pecuniary advantages and dimensional stability. While the toughness of a homogeneous PC matrix has been extensively investigated, examination for the toughness of heterogeneous blend systems such as PC/polypropylene (PP) blends has been limited. Furthermore, recent interest in highly flowable PCs (low-molecular-weight PCs with low ductility) has surfaced due to the large and geometrically complex plastic parts. Herein, the toughness for PC/PP blends and PC/PP/talc composites in a ductile and a brittle PC matrix was explored by using various toughness measurements such as notched Izod impact strength, falling dart impact, boss quasi-static energy/impact energy, and tensile toughness tests. In a ductile PC matrix [melt flow index (MFI) = 8], the incorporation of PP gradually reduced the toughness. On the other hand, the toughness was improved by 450% at 2 wt % PP in a brittle PC matrix (MFI = 19). Similarly, in the talc-induced brittle PC matrix, the toughness was enhanced at the PP loading from 2 to 10 wt %. The density of PC/PP blends was gradually reduced from 1.19 to 1.10 g cm⁻³ with increasing PP concentration from 0 to 20 wt %. Degradation, density, thermal behaviors, and morphology were also investigated. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47110.     

磷酸酯钠盐/滑石粉调控聚丙烯的退火研究

采用挤出共混法制得聚丙烯/磷酸酯钠盐/滑石粉(PP/NA-40/Talc)复合体系,研究了退火时间和退火温度对PP/NA-40/Talc复合体系力学性能、热变形温度以及结晶度的影响。通过DSC、XRD和FTIR证明了退火处理可以使PP/NA-40/Talc复合体系结晶度和力学性能提升。结果表明,PP/NA-40/Talc复合体系的力学性能、热变形温度以及结晶度与退火时间和退火温度成正相关;尤其是在120 ℃ 下退火处理2 h时,弯曲模量达到2516.0 MPa,热变形温度达到136.9 ℃ ,结晶度达到49.5 %。     

X射线衍射分段扫描法鉴别滑石粉中微量石棉

采用X射线衍射三段分步扫描鉴别滑石粉中微量石棉矿物。三次扫描采用不同扫描速度,能够检测到微量石棉的特征峰,提高检测滑石粉中石棉的分辨率,同时大大加快了分析速度。通过选择不同的扫描范围,可有效避免样品中共存物相干扰。配合显微镜观察法对“疑似”石棉进行判断,可有效鉴别滑石粉中石棉矿物是否已长成有害物质石棉。两种方法优势互补,方便快捷有效,可对滑石粉中微量石棉矿物及石棉进行快速鉴别。