Low temperature solid‐state extrusion of recycled poly(ethylene terephthalate) bottle scraps

The processing of poly(ethylene terephthalate) (PET) involves thermal and hydrolytic degradation of the polymer chain, which reduces not only the intrinsic viscosity and molecular weight, but also the mechanical properties of recycled materials. A novel PET/bisphenol A polycarbonate/styrene–ethylene–butylene–styrene alloy based on recycled PET scraps is prepared by low temperature solid‐state extrusion. Hydrolysis and thermal degradation of PET can be greatly reduced by low temperature solid‐state extrusion because the extrusion temperature is between the glass‐transition temperature and cold‐crystallization temperature of PET. Modification of recycled PET by low temperature solid‐state extrusion is an interesting method; it not only provides an easy method to recycle PET scraps by blend processing, but it can also form novel structures such as orientation, crystallization, and networks in the alloy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2692–2699, 2006     

Dielectric characterization of thermally aged recycled Polyethylene Terephthalate and Polyethylene Naphthalate reinforced with inorganic fillers

In order to assess the influence of the operating temperature on the dielectric properties of recycled Polyethylene Terephthalate (PET) and Polyethylene Naphthalate (PEN) reinforced with inorganic fillers, a dielectric and thermal investigation was undertaken. Specimens were thermally aged at several temperatures between 90 and 200°C for 360 h. The effect of thermal aging time on dielectric and thermal properties was also investigated. The dielectric response and breakdown strength properties were evaluated. Differential scanning calorimetry (DSC) measurements showed that the degree of crystallinity and the glass transition temperature increased with aging temperature and duration. The data obtained showed that these materials exhibited a good resistance to thermal aging at temperatures below 140°C. Furthermore, it was found that the dielectric strength of the recycled PET and PEN and their composites decreased considerably for temperatures of over 170°C. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers     

再生聚苯乙烯在混凝土中的应用研究综述

文章阐述了再生聚苯乙烯(EPS)颗粒在混凝土中的应用现状.首先对比了再生EPS与原生EPS的差异,阐述了目前所制备的再生EPS混凝土密度等级与力学性能之间的基本关系,并介绍了EPS混凝土热工性能、防火性能、隔声吸波等其他性能;其次,从EPS颗粒级配、掺量、纤维、改性剂、矿物掺合料、水灰比等方面阐述了影响再生EPS混凝土...     

The thermal,optical, flame retardant,and morphological consequence of embedding diacid‐capped ZnO into the recycled PET matrix

We extended our work to a fast and facile nanocomposites (NCs) manufacturing by incorporation of ZnO nanoparticles (NPs) on to a recycled poly(ethylene terephthalate) PET as a polymer matrix prepared by a dissolution/reprecipitation method. The surface of ZnO NPs was functionalized with synthesized optically active diacid containing alanine amino acid. Organo‐modified NPs which provided using solution blending technique through ultrasonic irradiation, were embedded into recycled PET. PET@ZnO/DA NCs containing different loadings of functionalized NPs (1, 3, 5 wt %) were investigated by thermal gravimetric analysis, field emission scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy and UV–visible spectroscopy. Morphological studies revealed uniformly dispersed ZnO/DA NPs in the polymer matrix. The crystalline nature of PET slightly improved as a function of the NPs concentration. Char yield in TGA and LOI values indicated that the obtained NCs were capable of exhibiting flame retardant properties. The NCs were found to exhibit more absorbance in the UV and visible region in compare to the neat PET. The effect of ultrasonication in different solvent on the morphology of the recycled polymer particle was also studied. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43433.     

不同类型再生细骨料对保温混凝土力学性能的影响

为了研究不同类型再生细骨料对玻化微珠保温混凝土力学性能的影响,将废弃混凝土再生细骨料和废弃黏土砖再生细骨料分别以25%、50%、75%和100%(体积分数)取代率取代保温混凝土中的天然河砂,并测试了再生保温混凝土的抗压强度、劈裂抗拉强度和弹性模量。结果表明: 25%是废弃混凝土再生细骨料在保温混凝土中的最优取代率;75%是废弃黏土砖再生细骨料在保温混凝土中的最优取代率。再生细骨料的压碎值和再生胶砂强度比在实际工程中可以有效区分不同类型再生细骨料的品质。废弃黏土砖再生细骨料中的火山灰材料可以有效提高再生保温混凝土的密实度,而废弃混凝土再生细骨料中残余的氢氧化钙却降低了再生保温混凝土的力学性能,因而废弃黏土砖再生细骨料具有更高的回收利用价值。     

Design and Characterization of a New Food Packaging Material by Recycling Blends Virgin and Recovered polyethylene terephthalate

This research is dealing with plastic wastes recycling environmental problem. The objective is the polyethylene terephthalate (PET) valorization from postconsumer bottles by the optimization of the most suitable virgin and recycled PET mixture to be used as food contact packaging. Mixtures of these materials were elaborated by extrusion and injection molding using different recycled PET rates. Rheological, mechanical, and thermal analyses were achieved, and then migration tests were investigated to assess the recycled PET compatibility for food contact packaging. The rheological analysis showed a PET degradation after the mechanical recycling, with PET viscosity decrease, compared to that of the virgin material. The blends properties showed that at low deformation, mechanical properties were significantly improved by adding recycled PET. Consequently, the new material was more rigid with a crystallinity degree improvement, increasing the materials resistance that enhanced their tenacity. However, at great deformations, the PET mixed materials were deteriorated through drastic ductility losses. The mixture 30/70 recycled/virgin PET seems to be the best blend. For all the studied mixtures, the overall migrations conformed the European Standard, allowing the use of the recycled PET for packaging as an issue in circular economy principles for a sustainable development. POLYM. ENG. SCI., 60: 250–256, 2019. © 2019 Society of Plastics Engineers     

Correlation of the morphology and thermooxidative degradation behavior of poly(ethylene terephthalate)–nitrile butadiene rubber–polycarbonate ternary blends

In this study, we prepared ternary poly(ethylene terephthalate) (PET)–nitrile butadiene rubber (NBR)–polycarbonate (PC) blends through a molten mixing procedure, and with a corotating extruder, we studied the morphology and thermodynamic properties of each purified polymer and the binary and ternary blends with different compositions. Dynamic mechanical analysis of both the PET–PC and PET–NBR samples showed individual loss peaks for each component, but in different ternary samples, the effects of different percentages of components (PC–PC and PET–NBR) were observed; this revealed changes in the loss peak locations. Individual loss peaks of PET and PC in the ternary PET–NBR–PC blends (81/9/10 and 63/30/7)—proof of the miscibility of the samples—were also observed in this study. The thermal properties of the samples were measured and examined with the thermogravimetric analysis and differential thermogravimetry testing methods. The activation energy and order of reaction values for the samples under an air atmosphere with single-rate methods of heating were studied. Finally, the relation between the type of morphology and the thermal degradation behavior was investigated. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47171.     

Effect of recycling on the properties of poly(ethylene terephthalate) films

Different proportions of recycled poly(ethylene terephthalate) (PET) films were blended with virgin PET and evaluated for physicomechanical, chemical, thermal, optical and barrier properties. The safety evaluation of the films for food contact applications has also been carried out. The variations in properties, such as tensile behaviour, impact strength, tear resistance, burst strength, gloss, haze, barrier properties, crystallization temperature and melting temperature, are reported. © 2000 Society of Chemical Industry     

Immobilization of Borate Waste Simulate in Cement-Water Extended Polyester Composite Based on Polyethylene Terephthalate Waste 1-Mechanical Properties of the Final Waste Forms

ABSTRACT

This paper discusses the suitability of Ordinary Portland Cement (OPC), water-extended polyester (WEP), based on recycled polyethylene terephthalate (PET), composite for stabilization/solidification (S/S) of borate waste solution originating from the primary coolant circuit of pressurized water reactors (PWRs).

This treatment is a new and attractive economical process that aims at keeping man and his environment healthy through controlling the dispersion of radioactive wastes (i.e., borate waste solution) and the solid plastic waste materials (i.e., PET).

Mechanical integrity of the WEP as well as its polymer composite (PC) with OPC was studied under different experimental conditions. Compressive strength measurements for the final waste forms of PC containing borate waste simulate were also evaluated using various compositions of the PC (e.g., water of hydration, polymer:cement ratio, borate content, etc.)

Based on the data obtained so far, it could be concluded that the candidate PC with the formulation of polymer:cement ratio 3%, water:cement ratio 40%, polymer:water of emulsion 80/20, and containing up to 3% by weight borate waste simulate shows compressive strength values acceptable for different transportation, storage, and disposal processes.     

含再生材料的PC/PET无卤阻燃合金加工稳定性

通过对再生聚对苯二甲酸乙二酯(PET–R)的多次挤出,研究了扩链对PET–R稳定性的影响。同时,也通过多次挤出和多次注塑的Regrind实验,研究了丙烯腈–苯乙烯塑料接枝甲基丙烯酸缩水甘油酯(AS-g-GMA)加入后再生聚碳酸酯(PC)/PET体系的相容性和稳定性,以及熔体流动速率和冲击强度的变化。通过11个月内的生产数据反映出,经过扩链和稳定化处理后的含再生材料的PC/PET无卤阻燃合金具有很好的加工稳定性。     

不同强度混凝土制造的再生骨料对高性能混凝土力学性能的影响(英文)

研究了由强度为30～100 MPa混凝土制造的再生骨料对高性能混凝土力学性能的影响。结果表明:利用30 MPa和45 MPa低强度混凝土制造的再生骨料搅拌的高性能混凝土,其力学性能明显下降;而由80MPa和100MPa的高强度混凝土制造的再生骨料搅拌的高性能混凝土,其28d抗压强度略高于由天然骨料搅拌的高性能混凝土的;再生骨料降低高性能混凝土的弹性模量,但降低量随着制造再生骨料混凝土的强度的增加而减少;28 d后再生骨料高性能混凝土的劈裂强度高于天然骨料高性能混凝土;由80 MPa和100 MPa高强度混凝土制造的再生骨料可以搅拌高性能混凝土。     

Experimental and numerical analysis of the thermal and mechanical behaviour of steel and recycled aggregate concrete composite elements exposed to fire

Using recycled aggregates in the production of concrete has been a viable alternative for sustainable development. Notwithstanding advanced information on this material at room temperature, its behavior when exposed to fire is still incipient. Thus, based on experimental analyses, the objective of this article is to evaluate the behavior of concrete produced with recycled aggregates for thermal insulation of steel elements, as well as to verify the physical and mechanical properties of these mixtures. For this purpose, eight prototypes, one made of steel and the others coated with different types of concrete, conventional and with recycled aggregates, were inserted in a horizontal oven and heated for 2 h. Based on experimental tests, numerical models were proposed and tested using the ABAQUS computational code, with consistent results when coherent thermal properties were adopted. The experimental results show that recycled aggregate concrete (RAC) has great thermal insulation potential and sustainable benefits, considering that the steel elements coated with this type of material, with the exception of those that underwent spalling, presented temperatures close to or below compared with concrete with natural aggregates. In this regard, it is observed that the thermal conductivity of RACs was inferior to conventional concrete, indicating that this material is a promising strategy for thermal insulation of steel structures.     

Unsaturated polyester resins from poly(ethylene terephthalate) waste for polymer concrete

Depolymerization of poly(ethylene terephthalate), PET, textile waste was performed with a manganese acetate catalyst. Different ratios of diethylene glycol (DG) to propylene glycol (PG) were used for glycolysis. The weight ratio of PET to the glycol mixture was 1:0.65. The glycolyzed products were analyzed for hydroxyl value and the amount of free glycol. These glycolyzed products were reacted with mixtures of sebacic acid (SE) and maleic anhydride (MA) to prepare a series of unsaturated polyesters having different molecular weights. The molecular weights of the unsaturated polyesters produced were determined by the end group analysis. The obtained polyesters were dissolved in styrene (Sty) monomer and their curing behavior was investigated. Polymer concretes (PC) made with these resins were investigated for their compressive strength. The data revealed that the properties of the PC based on recycled PET are comparable to PC made from virgin materials. We concluded that recycling of PET waste may provide a potentially lower cost source of resin, and its recycling in PC will also help reduce an environmental problem.     

Recycled milk pouch and virgin LDPE‐LLDPE‐based jute fiber composites

The present investigation deals with the thermo‐mechanical recycling of post consumer milk pouches (LDPE‐LLDPE blend) and its use as jute fiber composite materials for engineering applications. The mechanical, thermal, morphological, and dynamic‐mechanical properties of recycled milk pouch‐based jute fiber composites with different fiber contents were evaluated and compared with those of the virgin LDPE‐LLDPE/jute fiber composites. Effect of artificial weathering on mechanical properties of different formulated composites was determined. The recycled polymer‐based jute fiber composites showed inferior mechanical properties as well as poor thermal stability compared to those observed for virgin polymer/jute fiber composites. However, the jute‐composites made with (50:50) recycled milk pouch‐virgin LDPE‐LLDPE blend as polymer matrix indicated significantly superior properties in comparison to the recycled milk pouch/jute composites. Overall mechanical performances of the recycled and virgin polymeric composites were correlated by scanning electron microscopy (SEM). The dynamic mechanical analysis showed that storage modulus values were lower for recycled LDPE‐LLDPE/jute composites compared to virgin LDPE‐LLDPE/jute composites throughout the entire temperature range, but an increase in the storage modulus was observed for recycled‐virgin LDPE‐LLDPE/jute composites. POLYM. COMPOS. 28:78–88, 2007. © 2007 Society of Plastics Engineers     

废PET塑料纤维对再生混凝土基本性能的影响

为了提高再生混凝土(RAC)的力学性能,将废聚对苯二甲酸乙二酯(PET)塑料瓶剪成纤维条制成纤维再生混凝土(FRRAC)。通过纤维再生混凝土与再生混凝土的坍落度试验和强度试验,研究废PET塑料纤维长度、掺量对再生混凝土基本性能的影响,并进行强度影响因素的显著性分析和混凝土微观结构分析。结果表明：与不掺纤维的再生混凝土相比,纤维再生混凝土的流动性降低,且随废PET塑料纤维掺量、长度的增大而下降;掺PET纤维后,再生混凝土的抗压强度总体上有所提高,劈裂抗拉强度明显大幅提高。对于抗压强度,废PET塑料纤维的掺量影响显著;对于劈裂抗拉强度,纤维掺量、长度及二者交互作用均影响显著。掺PET纤维虽然会引入薄弱的界面过渡区,但适量时可使再生混凝土结构致密。     

Synthesis and applications of unsaturated polyester resins based on PET waste

Three types of unsaturated polyester resins were synthesized from the glycolysis of polyethylene terephthalate (PET) plastic waste, considering environment, cost and properties for their applications. These synthesized unsaturated polyester resins could be used for various construction processes and materials such as no dig pipelining (NDR-1), pultrusion (PLR-1) and polymer concrete (PCR-1). PET was taken from common soft-drink bottles, and ethylene glycol (EG), diethylene glycol (DEG) and MPdiol glycol mixtures were used for the depolymerization at molar ratios. The glycolyzed PET 1 ^st products (oligomers) were reacted with maleic anhydride, phthalic anhydride and dicyclopentadiene (DCPD) (especially for polymer concrete) to form unsaturated polyester resins with mixed styrene. The lab scale (1–5 kg) and pilot plant scale-up tests (200 kg) were experimented to evaluate the processing characteristics, viscosity, acid number and curing behaviors. The main properties such as hardness, flexural strength, tensile strength, heat distortion temperature, elongation, and chemical resistance were determined based on the various uses of the three resins. Furthermore, the applicability and the properties of these developed resins were verified through many real application tests.     

混凝土热工参数影响因素及理论计算

在国内外混凝土热工文献分析的基础上,研究了集料类型、含水量、混凝土配合比等因素对混凝土热工参数的影响,同时对比分析了已有的混凝土热工参数理论计算公式,并基于理论计算,给出了再生混凝土与高性能混凝土热工参数。     

Processing and thermal properties of composites based on recycled PET,sisal fibers,and renewable plasticizers

This investigation focuses on the preparation of bio‐based composites from recycled poly (ethylene terephthalate) (PET) and sisal fibers (3 cm, 15 wt %), via thermopressing process. Plasticizers derived from renewable raw materials are used, namely, glycerol, tributyl citrate (TBC) and castor oil (CO), to decrease the melting point of the recycled PET (T_m ∼ 265°C), which is sufficiently high to initiate the thermal decomposition of the lignocellulosic fiber. All used materials are characterized by thermogravimetric analysis and differential scanning calorimetry, and the composites are also characterized via dynamic mechanical thermal analysis. The storage modulus (30°C) and the tan δ peak values of CT [PET/sisal/TBC] indicate that TBC also acts as a compatibilizing agent at the interface fiber/PET, as well as a plasticizer. To compare different processing methods, rheometry/thermopressing and compression molding are used to prepare the recycled PET/sisal/glycerol/CO composites. These two different methods of processing show no significant influence on the thermal properties of these composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40386.     

High-impact-strength poly(ethylene terephthalate) (PET) from virgin and recycled resins

Poly(ethylene terephthalate) (PET) is a useful high-temperature plastic. Its shortcoming is that it has poor impact-strength properties. The impact strength of this polymer was dramatically improved by blending with a copolyester thermoplastic elastomer, or an acrylate core/shell elastomer. The addition of triphenyl phosphite (TPP) to the polyester elastomer/PET blends encouraged molecular weight buildup and resulted in improved impact strength and tensile properties. It was suspected that the phosphite interacts chemically with the components of the blend during processing and produces the improvements. Phosphorus-31 (³¹P)-NMR techniques have provided a direct spectroscopic probe of the chemical nature of the phosphite additive after the processing steps. Solution and solid-state spectra have revealed the presence of products in which the polymer chains are grafted and crosslinked through the phosphorus additive. Up to a 60-fold increase in impact strength of PET was obtained by blending with elastomers in the presence of TPP. Amorphous PET is susceptible to environmental stress cracking by many solvents, whereas crystalline PET or PET elastomer blends exhibit high resistance to solvent cracking. Similar improvements in properties were also realized when PET obtained from recycled soft drink bottles was used. © 1996 John Wiley & Sons, Inc.     

PC／RPET共混合金的研究

采用回收聚对苯二甲酸乙二酯增粘以及加入增韧剂的方法,通过一步法熔融共混挤出得到了具有良好力学性能的聚碳酸酯／回收ＰＥＴ（ＰＣ／ＲＰＥＴ）合金。通过适当地增粘ＲＰＥＴ以及合适地选择增韧剂,只需加入２．５％的增韧剂 以得到力学性能与纯ＰＣ工程塑料相当的ＰＣ／ＲＰＥＴ共混合金。同时成本比纯ＰＣ大幅度下降。