Preparation And Structure-activity Relationship Of 1,4-cyclohexane Dimethyl Alcohol Copolyesters

Polyester material is currently the most commonly used polymer material,with low cost,simple process,strong practicability of excellent characteristics,widely used in fiber,resin,film and many other fields.However,there are still many performance defects,such as low crystallization rate and poor impact performance,so it is urgent to optimize the performance of polyester materials.At present,the modification methods of polyester materials mainly include physical blending and chemical copolymerization,among which chemical copolymerization has the advantages of good compatibility,small addition amount and high efficiency compared with physical blending.But the chemical copolymerization method has complicated operation and difficult reaction control.Therefore,how to prepare polyester materials with adjustable structure and properties through chemical structure design and polymerization process optimization is still a challenge.Currently domestic commonly used1,4-cyclohexanedimethanol(1,4-cyclohexanedimethanol,CHDM)as the third monomer synthesis a series of excellent impact resistance,wear-resistant new copolyesters,materials in toughness,thermal properties,crystallization properties,methanol has broad prospect for development.In order to improve the toughness of polyester materials,a series of CHDM based copolyesters were prepared by chemical copolymerization with CHDM as the functional monomer,and the corresponding fiber materials were further prepared by melt spinning technology,which expanded the application field of copolyesters.The effects of CHDM content and CHDM cis-trans isomerism on the microstructure and mechanical properties of copolyesters were studied.Meanwhile,a series of CHDM based copolyesters with adjustable structure and properties were successfully prepared by optimizing the spinning process.The main research contents and conclusions are as follows:1.Study on the influence of CHDM monomer content on the structural properties of PETG copolyesters: CHDM monomer was introduced into polyethylene terephthalate by chemical copolymerization.Successful synthesis of a series of different CHDM content of PETG [Poly(ethylene terephthalate-co-1,4-cylclohexylenedimet-hylene terephthalate),PETG]copolyesters,The chemical structure of PETG was deeply analyzed,and the effect of CHDM content on crystallization melting,thermal stability,rheological properties and mechanical properties of PETG copolyester was systematically studied.The results showed that the overall mechanical properties of PETG copolyester decreased slightly with the gradual increase of CHDM content,and the toughness of the material improved obviously.The maximum elongation at break could reach about 170%.By adjusting the proportion of CHDM in PETG copolyester,the toughness of the material can be effectively improved while the strength is guaranteed.2.Study on the effect of CHDM three-dimensional configuration on the structural properties of PETG copolyesters: In order to further explore the influence of CHDM three-dimensional configuration on the structure and properties of PETG copollister material,this chapter firstly purified the CHDM monomer by cis-trans,then accurately controlled the CHDM cis-trans isomer content in PETG by chemical copolymerization method,and finally successfully prepared a series of PETG copollister with different cis-trans CHDM content.The effects of CHDM cis-trans isomer content on crystallization melting,thermal stability,rheological properties and mechanical properties of PETG copolyester were systematically studied.The results show that trans CHDM can effectively improve the thermal stability,crystallization capacity and mechanical properties of PETG copolyesters.Crystallinity increased from 21.96% to40.10%;When the tensile strength is increased from 39 MPa to 43.6MPa,the maximum elongation at break of PETG copolyester is about 190% when the content of trans CHDM is in the range of 68-80%.3.Effect of CHDM monomer content on structural properties of PECF copolyesters: These results indicate that CHDM can effectively improve the toughness of PETG copolyesters,but the development of 2,5-Furandicarboxylic acid(FDCA)polyester materials is limited by poor toughness.Therefore,based on the work of PETG,Continue to study CHDM monomer of PECF copolyesters [Poly(ethylene terephthalate-co-1,4-cylclohexylenedimethylene-co-furanoate,PECF)] structure performance are studied.A series of PECF copolyesters with different CHDM contents were prepared successfully by introducing CHDM monomer into PEF [Poly(ethylene furanoate,PEF)] polyester material by chemical copolymerization method.The effects of CHDM monomer content on the chemical structure,crystallization and melting,thermal stability,rheological properties and mechanical properties of PECF copolyesters were comprehensively analyzed.The results showed that: CHDM structure unit effectively improved the crystallization capacity of PEF copolyester,increasing the crystallinity from 29.29% to 39.13%,and the mechanical strength of copolyester showed a trend of increasing first and then decreasing.After adding CHDM structure unit,the tensile strength of copolyester decreased from 61.1MPa to58.3Mpa.In terms of toughness,the overall elongation at break first increased and then decreased with the increase of CHDM content,and the maximum elongation at break reached 188.2%.4.Study on the preparation and structural properties of CHDM based copolyester melt spinning fibers: In order to expand the application of CHDM based copolyesters in the field of fiber textile,this chapter comprehensively considers polymerization process,polyester properties and other factors,and selects PET,PETG and PECF polyester materials with specific content as objects for melt spinning forming research,and successfully produces a series of CHDM based melt spinning fibers by optimizing the spinning process.The effects of CHDM monomer and drafting process on the structural properties of copolyesters were systematically studied,and the relationships among chemical structure,spinning process,microstructure(crystal orientation,etc.)and macroscopic properties(mechanical properties,etc.)of copolyesters were emphatically expounded.The results show that the effect of drawing process on the properties of copolyester fibers is explained in detail from the condensed matter structure.The elongation at break of PECF copolyester fiber was increased from 4.6%to 190.5% by drafting process.