废PET的醇解及其在不饱和聚酯树脂合成中的应用

将采用甘油/二甘醇(DEG)混合醇为醇解剂,钛酸四丁酯为催化剂醇解废PET得到的醇解产物与顺酐、单元酸进行反应,制得不饱和聚酯树脂。通过红外光谱及粘度和力学性能测试等研究了醇解条件对PET醇解产物的影响及合成条件对不饱和聚酯树脂的性能影响。结果表明,n(甘油)∶n(DEG)=0.75∶1,n(混合醇)∶n(PET)=2∶1,钛酸四丁酯用量为PET质量的0.2%,醇解3 h条件下PET聚酯降解很彻底。n(顺酐)∶n(PET)=2∶1时顺丁烯二酸单辛酯封端甘油得到不饱和聚酯树脂的性能良好,该合成工艺简单、平稳可控,树脂色泽好、强度高、韧性好。     

乙二醇/二甘醇联合醇解废聚酯及其产物分析

探索了乙二醇/二甘醇联合醇解废聚酯(PET)工艺,并对醇解产物的性能进行了表征.结果表明:废PET与总二元醇质量比1 ∶ 2～1∶ 3、二甘醇(DEG)物质的量分数10％(占PET结构单元)、反应温度200℃、催化剂质量分数0.1％、反应时间1～1.5 h为高效的醇解反应条件.通过DSC、TG、FTIR、1H NMR等...     

废聚对苯二甲酸乙二醇酯的高温醇解研究

通过高温高压醇解法对废聚对苯二甲酸乙二醇酯(PET)在催化剂金属醋酸盐作用下,进行乙二醇醇解得到对苯二甲酸乙二醇酯(BHET),研究了废PET高温醇解的影响因素及工艺条件。结果表明:在高温醇解反应中,乙二醇与废PET的质量比和反应压力为主要影响因素,反应温度和解聚时间为次要影响因素;BHET收率随反应时间的延长、温度与压力的升高、乙二醇与废PET的质量比加大、催化剂的用量增大而增加,而二甘醇含量(除质量比因素)及醇解产物的熔点则随其相应降低;最佳醇解反应条件为压力0.4 MPa、乙二醇与废PET质量比0.5∶1.0、反应温度250℃、反应时间4 h,BHET收率达82%。     

废聚酯碎片醇解条件探讨

用小分子混合醇降解废聚酯碎片。考察了小分子多元醇、催化剂对反应产物的影响。该方法主要工艺参数如下:n(PET):n(PG)=1:2~3,醋酸锌质量分数为0.1%,醇解温度180~190℃,醇解时间6 h。     

高黏度聚酯的醇解工艺及其溶胀预处理研究

以乙二醇(EG)为解聚剂分别醇解特性黏数为0.670,1.014 dL/g的聚对苯二甲酸乙二醇酯(PET)切片及两者的混合物,对醇解产物进行了表征;通过单因素控制法考察了反应温度、EG与PET摩尔比、反应时间、催化剂添加量对醇解产物产率的影响;针对高黏度PET切片难以醇解的问题,提出了一种溶胀预处理工艺,研究了溶胀预处理PET切片的醇解动力学。结果表明：不同黏度PET切片的醇解产物的化学结构基本一致,主产物均为对苯二甲酸双羟乙酯(BHET);高黏度PET切片醇解体系的反应温度高于低黏度PET切片,高黏度PET切片适宜的醇解工艺为EG与PET摩尔比14：1、催化剂添加质量分数0.5%、反应时间240 min、反应温度200℃,此条件下产物BHET的产率为48.65%;高黏度PET切片在130℃经溶胀预处理后,结晶度由30.95%降至25.25%,反应速率常数由0.131 9 min^-1提高至0.171 9 min^-1,醇解速率大幅提高,溶胀预处理适宜的温度为高于PET切片的玻璃化转变温度且比其结晶温度低20～30℃。     

以废聚酯制备聚酯清漆中各因素对附着力影响研究

利用乙二醇和丙三醇混合对废PET进行醇解,再与顺丁烯二酸酐酯化制备了不饱和聚酯树脂,通过苯乙烯的交联固化反应得到不饱和聚酯漆涂层,研究了不同反应条件对涂层附着力的影响,确定最佳条件是PET、乙二醇和丙三醇的质量比为5:8:2,醇解时间为180-200min,酯化时间为70min。     

废PET醇解产物及在聚氨酯弹性体合成中的应用

以醋酸锌或3A分子筛为催化荆、一缩二乙二醇(DEG)为醇解剂,降解废聚对苯二甲酸乙二醇酯(PET),得到PET醇解产物;再用此废PET醇解产物合成聚氨酯弹性体(PUEs).讨论了醇解催化剂种类、nDEG:nPET重复单元、醇解产物添加量对PUEs性能的影响,同时采用TIG、DSC、X-射线衍射等分析手段对PUEs进行表...     

氧化镁烟气脱硫废渣制备催化剂及其醇解废PET的性能

采用氧化镁烟气脱硫废渣制备了类水滑石(HTLcs),将其焙烧制备了用以醇解废聚对苯二甲酸乙二酯(PET)的新型催化剂。对催化剂及降解产物进行了表征,并研究了煅烧温度对催化剂结构和性能的影响。在乙二醇溶剂中,用所制催化剂醇解废PET得到对苯二甲酸双羟乙酯(BHET),获得了最优实验条件:催化剂煅烧温度为500℃,醇解温度为198℃,催化剂质量分数为2.0%时,BHET的产率达69.34%。催化剂重复使用4次,其催化性能基本保持不变。该催化剂在固体废物处理和高分子降解领域具有潜在的应用价值。     

地沟油和废旧聚酯塑料的综合利用及研究

以地沟油为主要原料,经过甘油多元醇醇解后,再与聚酯饮料瓶的有效成分聚对苯二甲酸乙二酯酯化,合成了一种性能优异的改性醇酸树脂胶黏剂,并探讨了地沟油、甘油和聚酯之间的质量比及反应温度对合成的醇酸树脂胶黏剂性能的影响。研究结果表明,地沟油:甘油:聚酯的质量比为1:0.26:1.44,地沟油和甘油在220℃下进行醇解,然后加入聚酯在240℃下进行酯化反应,在此条件下合成的醇酸树脂油度为37%,涂膜后胶带的初粘力、持粘力和剥离强度均得到改善。     

聚酯宏观形态对其醇解反应的影响

以纯涤纶军装(1#)、涤棉军装(2#)、废瓶片(3#)、熔融挤出料(4#)、有光切片(5#)5种不同宏观形态聚酯(PET)产品为原料,乙二醇(EG)为醇解剂,碳酸钠为(Na2CO3)为催化剂,进行PET的醇解反应;研究了醇解时间、醇解温度及PET/EG质量比(mPET/mEG)等对PET醇解的影响,并对醇解产物进行表征。结果表明:5种不同宏观形态PET醇解后的主要产物均为对苯二甲酸双羟乙酯(BHET);催化剂Na2CO3能明显提高醇解速度,BHET产率随醇解时间、醇解温度、EG用量的增加而增加;最佳醇解条件是醇解时间60 min,醇解温度190℃,Na2CO3∶PET质量比为0.003∶1,mPET∶mEG为1∶4,5种不同宏观形态PET的醇解速度从大至小依次为2#,3#,1#,4#,5#,醇解后的BHET产率从大到小依次为5#,4#,3#,1#,2#,其BHET的色度L值大小依次为5#,3#,2#,4#,1#。     

过渡金属Mn取代多金属氧簇催化醇解废旧PET

合成了一种具有三明治结构的过渡金属Mn取代的多金属氧簇(POMs)催化剂Na12[WZnMn2(H2O)2(ZnW9O34)2],用于催化聚对苯二甲酸乙二醇酯(PET)的醇解过程,对反应温度、反应时间和催化剂量等实验条件进行了优化。结果表明,在催化剂量为PET质量的1.0%、质量比PET/EG(乙二醇)为1:4及190℃的条件下反应80 min,PET降解率可达100%,对苯二甲酸乙二醇酯(BHET)的收率达84.42%。     

Studies on synthesis and characterization of N‐alkyl terephthalamides using different amines from polyethylene terephthalate waste

This study deals with the degradation of polyethylene terephthalate (PET) waste through aminolysis with various amines. All of these degradation experiments were carried out at ambient temperature and at normal pressure. Although PET is known to be recycled in many ways, but still there is a need of development of other environment friendly recycling techniques. The amines used to study the degradation of PET waste were namely methylamine, ethylamine, and n‐butyl amine, respectively where the degradation of PET waste completes in 45 days. The aminolyzed products so obtained were characterized by using various conventional techniques such as spectroscopic techniques namely IR, NMR, and simultaneous differential scanning calorimeter (DSC). In the present research work, a useful method of PET recycling by using various amines was successfully established. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of novel polyurethanes based on aminolysis of poly(ethylene terephthalate) wastes,and evaluation of their thermal and mechanical properties

BACKGROUND: Much research is currently directed towards recycling post‐consumer poly(ethylene terephthalate) (PET) products for both environmental and economic reasons. Aminolysis of PET wastes using different amines, such as allylamine, morpholine, hydrazine and polyamines, leads to different reaction products as diamides of terephthalic acid, which do not possess any potential for further chemical reactions. In the past, the use of ethanolamine has been investigated for the aminolytic degradation of PET waste in the presence of different simple chemicals such as sodium acetate as catalysts. The product obtained, bis(2‐hydroxyethylene) terephthalamide (BHETA), has potential for further reactions to obtain useful products. Nevertheless, there has been no report on using recycled BHETA from PET to synthesize polyurethanes. RESULTS: In this research the product of aminolysis of PET waste, BHETA, was prepared. Then novel polyurethanes were synthesized based on the BHETA prepared, 1,4‐butanediol, ether‐type polyol and various molar ratios of hexamethylene diisocyanate. To evaluate the effect of BHETA, the properties of the polyurethanes without and with BHETA were compared. Fourier transform infrared spectra, thermal transitions, degradation, swelling ratio and chemical resistance of the synthesized polyurethanes were investigated. Also, the polyurethanes were applied as adhesives on various substrates. Comparison of the maximum bond strength of the synthesized polyurethane to that of commercial adhesives shows an about 2.2‐fold increase. CONCLUSION: It is possible to synthesize new polyurethanes with interesting properties using BHETA as an aminolysis product of PET waste. These kinds of materials have potential for many applications, such as adhesives and coatings. Copyright © 2008 Society of Chemical Industry     

Unsaturated polyester resin via chemical recycling of off‐grade poly(ethylene terephthalate)

BACKGROUND: The chemical recycling of poly(ethylene terephthalate) (PET), e.g. bottles and fibre wastes, has been studied for many years. Among several methods proposed for chemical recycling of waste PET, glycolysis makes it possible to employ very low amounts of reactants and lower temperatures and pressures compared with critical methanol and thermal degradation. Furthermore, unlike hydrolysis under acidic or basic conditions, glycolysis does not cause any problems related to corrosion and pollution. RESULTS: PET from off‐grades of industrial manufacture was depolymerized using excess glycol. The effects of the reaction time, volume of glycol and catalyst concentrations on the yield of the glycolysis products were investigated. A reaction time of 3 h, weight ratio (catalyst to PET) of 0.25 wt% and PET to ethylene glycol molar ratio of 1:5 were determined as suitable conditions for depolymerization. Then, the reaction of polyesterification of maleic anhydride (MA) and glycolysed products of PET was successfully performed at 160 and 190 °C for 8 h. CONCLUSION: Differential scanning calorimetry and vapour pressure osmometry results for the product of the glycolysis reactions, under suitable condition, confirmed the structure of the desired product. This sample underwent reaction with MA to produce unsaturated polyester resin (UPR). The results of Fourier transform infrared and NMR spectroscopy confirmed that the UPR had been synthesized successfully. This is the first direct report on the glycolysis reaction of off‐grade products of petrochemical companies in order to regenerate raw materials or other secondary value‐added products. Copyright © 2009 Society of Chemical Industry     

废聚酯再资源化制备涂料研究进展

介绍了国内外化学降解废聚酯制备涂料的研究进展。分别从聚酯树脂涂料，醇酸树脂涂料以及聚氨酯涂料讨论了废聚酯回收利用的开发前景，并指出中国应大力加强废聚酯再资源化的研究开发工作。     

Investigation of the effect of hydrolysis products of postconsumer polyethylene terephthalate bottles on the properties of alkyd resins

Hydrolysis of waste polyethylene terephthalate (PET) flakes obtained from grinding postconsumer bottles was carried out at 200–230°C and molar ratios of PET/H₂O were taken as 1/5; 1/10; 1/20. The reaction products, when extracted with boiling water, yielded a water soluble crystallizable fraction (WSCF) and a water insoluble fraction (WIF). These fractions were characterized by acid and hydroxyl value determinations and DSC analysis. WSCF and WIF were used for preparation of alkyd resins. Five long oil alkyd resins were prepared from phthalic anhydride (PA) (reference alkyd resin) or hydrolysis products of the waste PET (PET‐based alkyd resin), pentaerithrithol (PE), soybean oil fatty acid (SOFA), and ethylene glycol (EG). Film properties and thermal degradation stabilities of these alkyd resins were investigated. Drying time, hardness, alkaline resistance, and thermal oxidative degradation resistance of the PET‐based alkyd resins are better than these properties of reference resin. The results show that hydrolysis products of waste PET obtained from postconsumer bottles are suitable for manufacturing of alkyd resins. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Chain extension and degradation during reactive processing of PET in the presence of triphenyl phosphite

Poly(ethylene terephthalate) (PET) is chemically degraded during processing and/or using by a number of sources including temperature, humidity, and ultraviolet radiation. As a consequence, a large loss in engineering properties is observed when PET products are recycled. To overcome this problem, various types of chain extenders were developed in an attempt to recover the polymer molecular sizes by chemical reactions during processing. This work investigates the use of triphenyl phosphite (TPP) as a chain extender of virgin and recycled PET. Compounds with 1 and 3% of TPP were prepared and processed under various conditions using a torque rheometer. An increase in torque during mixing was associated with chain extension reactions whereas the observed decrease in torque afterwards was due to chemical degradation. The optimum processing conditions were reached (260°C, 1% chain extender), with a maximum in chain extension and a minimum in subsequent degradation. An important finding of this work was that the chemical degradation of chain extended PET occurs very easily during storage and it was considered to be a result of the influence of by‐products of TPP reaction with PET. The extraction of these products with acetone was shown to be quite effective, with a considerable stability during storage. This work also showed that the recycled PET is much less able to react with TPP in comparison with the virgin polymer. POLYM. ENG. SCI., 47:2155–2163, 2007. © 2007 Society of Plastics Engineers     

废弃PET化学回收及制备不饱和聚酯树脂的研究进展

随着聚对苯二甲酸乙二醇酯（PET）材料用量的大幅增长,大量废弃PET制品堆积造成的环境污染问题日益突出,其回收利用技术也随之广受关注。在不同的PET回收方法中,将PET降解为单体或低聚物的化学回收是效率最高、产物利用价值最大的方法,但也存在反应条件苛刻、产物收率低等问题。本文详细梳理了水解法、甲醇醇解法、二元醇醇解法、胺解法和氨解法等化学回收方法的主要特点以及微波加热、离子液体、纳米技术等新兴技术在PET化学回收过程中的应用概况。通过对各种化学回收工艺的比较,文中得出二元醇醇解法是最具商业应用价值方法的结论。在此基础上,文中重点介绍了PET的二元醇解以及进一步制备不饱和聚酯树脂的化学过程、发展现状、制约因素和改进措施。分析表明,由PET二元醇解产物制备不饱和聚酯树脂是提高废弃PET资源化效率、丰富原料供给、推动产品升级的重要途径,开发高效、廉价、环保的新型催化剂或酶催化技术是废弃PET回收领域今后主要的发展方向。     

The use of aminolysis,aminoglycolysis, and simultaneous aminolysis–hydrolysis products of waste PET for production of paint binder

This work is concerned with the use of aminolysis, aminoglycolysis, and simultaneous aminolysis–hydrolysis products of waste PET for production of paint binder based on alkyd resin. For this purpose, first, aminolysis, aminoglycolysis, and simultaneous hydrolysis–aminolysis reactions of waste PET were carried out in the presence of different chemical agents in xylene medium at high pressures. Reactions of waste PET flakes obtained from grinding postconsumer water bottles were carried out in an autoclave at higher temperatures. Then, four alkyd resins, formulated to have oil content 40–50%, were prepared using these depolymerization products. One of resins is “reference alkyd resin” which was prepared by using soybean oil fatty acid, phthalic anhydride, glycerine, and ethylene glycol for comparison. Other three alkyds are “depolymerization product‐based alkyd resins” in which depolymerization products is used instead of ethylene glycol. Then, the physical and chemical surface coating properties and thermal behaviors of alkyd resins films were investigated comparatively. As a result, we concluded that aminolysis, aminoglycolysis, and simultaneous aminolysis‐hydrolysis products of waste PET are suitable for manufacturing both air drying and oven curing paint binder based on alkyd resins. The film prepared from alkyd resin based on simultaneous aminolysis‐hydrolysis product showed extremely good surface coating properties and thermal stability. POLYM. ENG. SCI., 54:2272–2281, 2014. © 2013 Society of Plastics Engineers     

Modification of Waste Poly(Ethylene Terephthalate) (PET) by Using Poly(L-Lactic Acid) (PLA) and Hydrolytic Stability

The purpose of this study is the preparation of hydrolytically degradable copolymers of waste poly(ethylene terephthalate) (PET). To achieve this, we modified PET by using biodegradable poly(lactic acid) (PLA). Modification reactions were carried out in o-nitrophenol as solvent at 140 and 170°C for 8, 16, and 24 h in the presence of dibutil tin oxide (DBTO) as catalyst. The amount of the total polymers (PLA and PET) in the reaction mixture was 30% by weight, and the weight ratios of PLA/PET were 10/90, 50/50, and 90/10. These modified products were characterized by Fourier transform infrared spectrometer (FTIR), differential scanning calorimeter (DSC) as well as by hydrolytic degradation determinations. Hydrolytic degradations of the products were determined gravimetrically. Disc-shaped samples were placed in tubes containing phosphate buffer solution of pH 7.2 and kept in a water bath at 60°C for 28 days. The weight loss of the products after hydrolytic degradation ranged from 1.25% to 48.75% after 28 days.