Design Synthesis And Properties Of Polycarbonate Materials Based On Citric Acid And Polyester Materials Based On Camphor

The polyester material is generally obtained from polyhydric alcohol and polybasic acid.Two successive steps are involed in the synthetic process,namely,transesterification or direct esterification,followed by polydondensation reactions.Polyester materials are widely used in the packaging industry,electronic appliances,medicalhealth construction,automotive and other fields.With the increasing proportion of polyester materials in daily life,the demand for polyester has increased sharply,and the raw materials of polyester materials are heavily dependent on petroleum-based resources.Petroleum resources and oil resources have been excessively exploited.In order to reduce the dependence on petroleum resources,the use of bio-based monomers to replace the petroleum-based monomers is a hot topic.1.To obtain thermally stable monomer while at the same time retain rigidity,we developed a novel bicyclic diol octahydro-2,5-pentalenediol?OPD?from naturally occurring citric acid.A series of copolycarbonates?co-PCs?were synthesized by melt polymerization,starting from OPD,1,4-cyclohexanedimethanol?CHDM?and diphenyl carbonate?DPC?.All polycarbonates exhibited amorphous characteristics with glass transition temperatures increased with increasing the OPD content.Dynamic mechanical analysis?DMA?revealed the sub T_g?-relaxations at low temperatures originated from the CHDM conformational transition,indicative of the possibility of impact-resistance.Morphological analysis of the fracture surfaces indicated that the toughening mechanism under tensile was shear yielding of the matrix triggered by internal cavitation.The incorporation of OPD steadily increased the Young?s modulus,from 482.0 MPa to 756.6 MPa,with the OPD fraction increased from 0mol%to 30 mol%.As the OPD content increased,a“ductile-to-brittle”transition occurred due to their low M_ns and the low entangled strand density.2.Due to the rigid structure of camphor diol,it is speculated that camphor diol can effectively increase the glass ring transition temperature of the polymer.A series of polyester materialswereobtainedbymeltpolymerizationfromcamphordiol,1,4-cyclohexanedimethanol,dimethyl terephthalate,and dimethyl-2,5-furandicarboxylate.The structure of the polyester material is characterized by nuclear magnetic resonance spectrometer and gel permeation chromatography.The thermal properties of the polyester material are analyzed by thermogravimetric analysis and differential scanning calorimeter.The mechanical properties of the polymer were tested by universal tension machine.It was concluded that camphor diol is a good rigid monomer that can effectively increase the T_g of the polymer.