Study On Transparent Thermoplastic Copoly(Ether Ester) Elastomer

Thermoplastic elastomers?TPEs?were proud of "the third generation of rubber".Thermoplastic copoly?ether ester?elastomer?TPC-EE?is one subcategory of TPEs which has excellent dynamic mechanical properties and thermostability.TPC-EE comprising a block copolymer of alternating hard and soft segments,the chemical linkages in the main chain being ester and/or ether,and its soft segments with ester and ether linkages.TPC-EE owns excellent elasticity which is similar to vulcanized rubber over the range of temperature from-50? to 120?.When temperature above 200?,TPC-EE will be melted and be processed.TPC-EE has remarkable properties due to its unique super molecular structure.Traditional TPC-EE?P4GT-PTMOT?based on multiple tetramethylene terephthalate?P4GT?crystalline polyester as the hard segments and copoly?tetramethylene oxide?terephthalate?PTMOT?amorphous polyether as the soft segments.PTMOTs form a liquid-like phase at ambient temperature and are thought to provide the elastomeric character to the polymer.P4GTs are capable crystallization to form a thermally reversible network structure.The physical crosslinks resulting from this association of the hard segments provide for dimensional stability and minimize cold flow.But TPC-EE products usually show milky white or milky yellow,their light transmittance are less than 80%.So they are lack of application in packaging fields for cosmetics,food and beverage,pharmaceutical.Through the study of phase structure of the traditional TPC-EE,we found that the opacity of the products is resulting from the sizes of crystal grains which have been formed by the hard segments are too big.Novel TPC-EE which has excellent transparent performance is gained by designing new hard segments,and adjusting the super molecule structure of TPC-EE.The innovation of this thesis and research results are as follows:1?In the synthesis of P?4GT-co-CHMT?-b-PTMOT,dimethyl terephthalate?DMT?,1,4-butanediol?BDO?,1,4-cyclohexanedimethanol?CHDM?,and polytetramethylene oxide?PTMO?,germanium oxide catalytic composites were used.The first step was transesterification in atmospheric pressure and then low pressure polycondensation method was processed in the second step,and a series of novel TPC-EE were successfully prepared.2?In the synthesis of PCCD-PTMOT,1,4-cyclohexane dicarboxylic acid?CHDA?was used to replace DMT,and a series of novel TPC-EE were successfully prepared.3?In this paper,we designed and produced three transparent polymer blends of t-TPC-EE/PC,t-TPC-EE/SEBS based on transparent TPC-EE?t-TPC-EE?,which respectively used Brabender mixer or co-rotating twin-screw extruders.This thesis studied on the morphology behavior,thermal and mechanical properties of the transparent TPC-EE.This paper is divided into four parts:1?To study the effect of titanium catalytic system,germanium catalytic system and titanium-silicon catalytic system on the structure and properties of P?4GT-co-4GP?-b-PTMOT.We replaced part of dimethyl terephthalate?DMT?by dimethyl phthalate?DMP?,with BDO and PTMO as the raw materials,through atmospheric transesterification reaction and vacuum condensation reaction to prepare TPC-EE.Gel permeation chromatography?GPC?experimental results show that using three catalytic systems we can get ploymers whose average molecular weights are about 28,000 g/mol.The repot of IR and NMR characterization show that TPC-EE in line with expectations chemical linkages of molecular chain structure.At the same time,the samples with good heat resistance,mechanical properties and good processability.The main differences between the three catalytic systems are:the reaction activity of the Ge system is relatively low,the high temperature and high vacuum condensation time needs 59min,and the Ti system only needs 29min.However,the optical properties of the Ge system showed obvious advantages.The transmittance of TPC-EE prepared by Ge was 69%which was significantly better than that 52%?TPC-EE prepared by Ti?and 55%?TPC-EE prepared by Ti-Si?.The results of polarizing microscope?POM?showed that the numbers and sizes of the hard segment crystal grains were less in the sample prepared by germanium.2.Using CHDM replaced the BDO,with DMT and PTMO as the raw materials,used germanium catalyst system to synthesis P?4GT-co-CHMT?-b-PTMOT.The experimental results show that the average molecular weight of TPC-EE was around 30,000 g/mol.When the mass content of soft segments?PTMOT?was constant 40%,the hardness of TPC-EE is ahout Shore 54D±3D.With copolymerization hard chain segment PCHMT from 0 to 60%,the transmittance of TPC-EE from 53%to 88%,this phenomenon because of PCHMT chain segment has a fast crystallization nucleation rate and a slow growth rate,with increase content of PCHMT the crystallization nucleation increase,the grain size decreases.Study on synthesis of PCHMT-PTMOT,with content of PCHMT increased from 40%to 80%,the hardness of TPC-EE increased from 42D to 69D,the crystallinity increased from 15.2%to 19.8%.At the same time,the transmittance of samples increased from 66%to 89%and then reduced to 71%,the highest point appeared at 60%PCHMT content.The reason for the emergence of light transmittance is that the nucleation rate of PCHMT is fast,and the crystal growth rate is slow.When the amount of PCHMT less than 60%,with the increase of the content of PCHMT,an increase in the number of nuclears,most hard segments quickly into the nucleus and the molecular chain segment movement was restricted,the crystal growth was restricted,grain size does not change,TPC-EE has higher transmittance.But when the PCHMT amount exceeds 60%,increase of the number of nuclear accounted for assembly nuclear ratio of the number of changes is very small,on the other hand,the distribution density of PCHMT chain segment is too big,free PCHMT chain segment easily accessible to match the nucleation of crystal grains,the crystal grains growth,the transmittance of TPC-EE decreased.So the best comprehensive performance of the samples is PCHMT₆₀-PTMOT₄₀,the transmittance is 89%,the hardness is 45D,the tensile strength is 39.2MPa,the elongation at break is 693%.3?We synthesis PCCD-PTMOD by using CHDA replace the DMT.The sample PCCD₆₀-PTMOD₄₀ owns good properties,that the transmittance is 93%,the hardness is 55D,the tensile strength is 22.9MPa,the elongation at break is 935%.Study on synthesis of PCCD-PTMOT,with the content of PCCD increased from 40%to 70%,the hardness of TPC-EE increased from 34D to 62D,the crystallinity increased from 14.1%to 19.7%.At the same time,the transmittance of samples increased from 65%to 93%and then reduced to 75%,the highest point appeared at 60%PCCD content.The reason for the emergence of transmittance is that the nucleation rate of PCCD is fast,and the crystal growth rate is slow.The role of PCCD in PCCD-PTMOD is the same as PCHMT in PCHMT-PTMOT.4.Using transparent PCCD-PTMOD as matrix resin,adding styrene ethylene butylene styrene copolymer?SEBS?or polycarbonate?PC?,three series of transparent polymer blends were prepared through Brabender mixer or parallel corotating twin screw extruders.Test results show that the blends has excellent thermostability,dynamic mechanical properties and processing performance,while maintaining good optical properties.Study on t-TPC-EE/PC alloys,the hardness and strength of the t-TPC-EE creased by blending with PC,and the cost of t-TPC-EE was reduced.The alloy which hardness is shore 75D with the transmittance is 86%,tensile strength is 48MPa,the elongation is 380%.Study on t-TPC-EE/SEBS alloys,the alloy which hardness is shore 25D?80A?with the transmittance is 82%,the tensile strength is 23MPa,the elongation is 550%.In brief,based on light transmit in multiphase polymer,and through the construction of introducing novel saturation and volume larger structural units replace the structure unit of TPC-EE molecular chain in the unsaturated and small volume segment,we successed synthesis a series novel transparent TPC-EE,studied on effects of catalytic system and recipes,we analysis of the variation in light transmittance.And further extend the hardness range of transparent TPC-EE by melt blend with thermoplastic polymers.Some transparent TPC-EE blends were prepared with hardness range from Shore 25D to 75D.Transparent TPC-EE can be widely used in packaging for medicine,food,cosmetics and other products.This paper provides important scientific data for the preparation,structure and properties of the novel transparent TPC-EE,so it has a certain value of theory and application.