Design,Synthesis And Properties Of Polyester Materials Based On D-Camphor

Due to the increasing concerns on sustainable development and minimizing the impact of materials on the environment,bio-based monomers and polymers have attracted a great deal of interest from both academic and industrial fields.To address the above issues,various groups of bio-based monomers were used in this respect,one class has received special attention,named the carbohydrates.Previous investigations on structure-property relationships revealed that an amorphous,high-T_g polymers have the potential to be used as beverage packing,optical glasses and automotives because in many cases they have superior dimensional stability,mechanical strength,high transparency and UV stability.Despite the apparent merits,these carbohydrate-based diols still suffer from several drawbacks,such as limited reactivity and their high sensitivity to heat.So it is very impotant to develop an inexpensive,sustainable,high reactivity and thermostability monomer.1.With the aim to search rigid monomer while at the same time retain reactivity,we have synthesised a noble bio-based diol monomer?1R,3S?-?1?-cis-1,2,2-trimethylcyclopentane-1,3-dimethanol?TCDM?from naturally occuring natural-?D?-camphor.Owing to the bulky trimethyl substituted cyclopentyl structure,TCDM is supposed to have perfect rigidity and higher thermal stability.Here we report a series of polymers based on TCDM and linear?,?-diacids or dimrthyl ester.For comparative purposes,two sets of 1,3-cyclopentanedimethanol-based?CPDM?and 1,6-hexanediol-based?HDO?polyesters were also synthesized with molecular weights in the higher range using a similar procedure.It is worth noticing that the monomer TCDM is unsymmetric and it will generate aregic polymers,the incorporation of the TCDM units in the chain occurring essentially at random.A relatively high T_5%of 342oC,outstanding high T_g up to 115oC and the Young's modulus up to 1857 MPa were detected for fully DMT-based polyesters,confirming the excellent thermal stability and rigidity of TCDM.A systematic study on structure-thermal properties relations among relevant series of polyesters,such as PE-nGalxs polymers based on 2,3:4,5-di-O-methylene-galactaric acid?Galx?,revealed several interesting differences in glass transition temperatures,which are elucidated by van Krevelen's group contribution method.This work addresses some critical needs for high performance polymers such as improving the sustainability of raw materials and achieving both high T_g values and thermal stability.2.?1R,3S?-?1?-cis-1,2,2-trimethylcyclopentane-1,3-dimethanol?TCDM?is a rigid alicyclic diol derived from the naturally occurring camphor.In order to improve the low glass transition temperature?T_g?,slow degradation rate and brittle nature of poly?butylene succinate??PBS?,two series of TCDM-containing PBS copolyesters were synthesized via melt polycondensation?MP?and reactive blending?RB?,respectively.Starting from TCDM,1,4-butanediol?B?and dimethyl succinate?S?,random copolyesters?abbreviated as RPTxByS?were obtained after MP,while RB afforded copolyesters with a block like chemical microstructure?abbreviated as BPT_xB_yS?.The T_g increased upon incorporation of the TCDM and no noteworthy differences were detected in thethermalstability of theRPTxByS and BPTxByS containing similar amounts of TCDM.Part of the RPTx ByS and BPTxByS copolyesters are semicrystalline materials and the monoclinic crystal structure of PBS is retained in these semicrystalline copolyesters.With the same TCDM content,BPTxByS displayed higher melting points,a higher crystallization rate from the melt,and better mechanical strength,due to the longer PBS sequences present in the copolyester backbone compared to RPTxByS.The incorporation of TCDM in the copolyester backbone enhanced the hydrolytic degradation of the materials with respect to the degradation of neat PBS.In this work,RB was demonstrated to be a very suitable technique for the modification of low melting point aliphatic polyester,leading to bio-based non-random copolyesters with remarkable mechanical and thermal properties.3.Poly?ethylene 2,5-furandicarboxylate??PEF?is gaining more and more interest as a bio-based polymer,particularly due to its remarkable gas barrier properties compared to poly?ethylene terephthalate?while being chemically comparable.A series of bio-based copolyesters,poly?ethylene2,5-furandicarboxylate-co-ethylene?1R,3S?-?1?-cis-1,2,2-trimethylcyclopentane-1,3-dimethanol??RPT_xE_yF and BPT_xE_yF?were synthesized from ethylene glycol?EG?,2,5-furandicarboxylic acid?FDCA?and TCDM via melt polycondensation?MP?and reactive blending?RB?.The chemical structure,compositions and sequence distributions were determined by ¹H-NMR and ¹³C-NMR.The molecular weight,thermal properties and thermal stabilities were investigated by GPC,DSC and TGA,respectively.All RPTxEyF showed characteristic of random copolymer,BPTxEyF were with a block like chemical microstructures,and their composition could be controlled by the feed molar ratio of EG to TCDM.DSC results showed that RPTxEyF and BPTxEyF were amorphous,while increasing the TCDM content,increased the glass transition temperatures?T_g?of RPTxEyF and BPTxEyF increased.Moreover,the thermal stabilities of all RPTxEyF and BPTxEyF remained unchanged.