Research on synthesis of polyurethane based on a new chain extender obtained from waste polyethylene terephthalate

Abstract

Bis(2-hydroxyethyl) terephthalate (BHET), the alcoholysis monomer of waste polyethylene terephthalate, can form a cross-linked network structure with the polyurethane main chain because of the unique structure of active hydroxyl groups. In this work, organic small molecular BHET was applied as a new chain extender in polyurethane synthesis. A green and facile method was proposed to fabricate waterborne polyurethane (WPU) by recycling waste polyester. It was found that WPU was successfully prepared by using BHET as chain extender. Compared with polyurethane prepared by small molecular chain extender 1,4-butanediol (BDO), mechanical strength and thermal stability of polyurethane were remarkably enhanced by the incorporation of BHET. Meanwhile, the water absorption rate of the polyurethane is reduced. The tensile strength of WPU/BDO materials with 3.77 wt% BDO was 5.3 MPa, while WPU/BHET materials with 3.77 wt% BHET was 9.4 MPa. Furthermore, the elongation at break of WPU/BHET materials reached the maximum with 5.66 wt% BHET. Moreover, WPU/BHET materials prepared by using BHET as a chain extender have better thermal stability in high temperature environments. BHET with distinctive structure and the uniform dispersion will have more potentials for the preparation of high-performance polyurethane composites, especially for green recycling of polyester materials.bis(2-hydroxyethyl) terephthalate (BHET), chain extender, cross-linked network, mechanical strength, waterborne polyurethane (WPU)

Bis(2-hydroxyethyl) Terephthalate-Modified Ti3C2Tx/Graphene Nanohybrids as Three-Dimensional Functional Chain Extenders for Polyurethane Composite Films with Strain-Sensing and Conductive Properties

“…Fabrication of 3D-Functionalized Ti 3 C 2 T x (B-rGO@ Ti 3 C 2 T x ). Our team has successfully obtained BHET from waste PET by alcoholysis, 4 and the preparation process and characterizations of BHET are shown in Figures S1 and S2 in the Supporting Information. The GO was fabricated by the Hummers method.…”

“…The alcoholysis monomer bis­(2-hydroxyethyl) terephthalate (BHET) of waste polyethylene terephthalate (PET) has been chemically synthesized to obtain PET-based copolyesters and unsaturated polyesters . It can also be used as a chain extender for polyurethane and an organic modifier for 2D materials such as MXene and graphene . Our team has previously used BHET-modified reduced graphene oxide (BHET-rGO) to prepare WPU/BHET-rGO nanocomposites with excellent properties through in situ polymerization .…”

Preparation of high‐performance polyurethane elastomers via direct use of alcoholyzed waste PET by high molecular weight polyester diols

“…Simultaneously, the introduction of PET repeating units via transesterification can be viewed as a modification of the original diols, potentially enhancing the thermal stability and mechanical properties of the resulting PUEs. 13 Materials required for preparation of PUEs: N,N-Dimethylformamide (DMF) and Dibutyltin dilaurate (DBTDL) were obtained from Shanghai Macklin Biochemical Technology Co., Ltd., Hexamethylene diisocyanate (HDI) and Butane-1, 4-diol (BDO) were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.…”

“…This approach not only helps to conserve petroleum resources but also introduces PET-related structures, such as benzene rings, that are expected to enhance the mechanical properties and thermal stability of the resulting PUEs. 13,14 A "three-step" route has been developed for the highvalue transformation of waste PET into PUEs. Firstly, PET is degraded by low molecular weight diols such as ethylene glycol, 1,3-propanediol, and 1,4-butanediol.…”

The synergetic effect of bis(2‐hydroxyethyl) terephthalate from glycolysis of poly(ethylene terephthalate) on the intumescent flame retardancy of waterborne polyurethane

“…According to the previous research of our group, 31,32 BHET was obtained according to the following scheme. Briefly, PET waste and EG were mixed at a mass ratio of 1:4 with 5 wt% (referring to the mass of PET) of zinc acetate.…”