Study On Synthesis Of Water-soluble Aliphatic Polyester Coatings And Their Modification By In-situ Composite Method

PVC is generally used as textile coatings,but it is urgent to be substituted due to releasing some hazardous substances during process,recycle hardly and not decomposing naturally, water-soluble aliphatic polyester(WSAP)has good biodegradability and bio- compatibility,and can be used as environmental-friendly,However,there have a few publications to report water-soluble aliphatic polyester as textile coatings.In this thesis,Series of WSAP were synthesized by using 2,2-Dimethylol Propionic Acid (DMPA)as water-soluble group,adipic acid as bi-functional carboxylic acid monomer, 2,2-Dimenthyl-1,3-propandiol(NPG)and 1,6-Hexandiol as bi-functional alcohol monomer,and methyldiethanol-amine as hydrophilic agent,CYMEL303 as cross-link agent.The process of aliphatic polyester matrix synthesis,water-soluble modification of matrix and thermal crosslink of water soluble polyester had been systematically studied,and their molecular structure and physical properties had been characterized by acid value,OH value,GPC,FT-IR and NMR.The water-resistance,crystallinity,thermal properties,surface morphology of the coating film had been investigated.The main results obtained were as follows:The effect of acid-alcohol ratio,the component of alcohol ratio,the amount of DMPA,the reaction temperature on synthesis process and polyester matrix obtained were investigated in detail.The chemical structure,acid value,OH value,number molecular weight of polyester matrix were measured by FTIR,NMR and GPC.It was shown that the optimum conditions were as follows:the molar ratio of-OH/-COOH was 1.2/1,the reaction temperature 135℃,and in the nitrogen atmosphere.The reaction should be stopped when acid value of reaction system is near to 30 mg KOH/g.The polyester matrix obtained was transparent with pale yellow,has 80 OH value, 1900～2500 number molecular weight and good flowing property.The effect of the kind of amine and its usage on water-solubility of polyester matrix,and the effect of the amount of cross-linking agent,curing temperature on properties of coating film were systematically investigated.The optimum condition was methyldiethanolamine as neutralizer and 1.2 time of the acid number adding amount,hexakis-(methoxymethyl)-melamine(CYMEL303)as cross-linking agent and the total of the acid number and the OH number of polyester matrix, 20min curing time at 150℃.The coating film obtained was smooth;elastic without adhering,and no obvious bubble phenomena and yellowish,and its hardness was B level.The molecule structure of the coating film was investigated by FT-IR.It was shown that the cross-linking reaction between the polyester matrix and CYMEL 303 had been taken place.The in-situ formation in polyester matrix had been studied.The in-situ composite polyester with moderate viscosity and polydispersity was prepared when the content of Ti was 1%,the esterification temperature was 135℃and polycondensation temperature was 180℃.With the increase the content of the Ti,the PDI of the in-situ polyester rise correspondingly.The coordination compound of the titanium was investigated by the FT-IR.The application performance of water-soluble aliphatic polyester coating and in-situ polyester coating was studied by various methods including water-resistance,adhesion pencil hardness,crystallinity,thermal properties,and surface morphology.Compared with the water-soluble aliphatic polyester,the in-situ polyester coatings have advantages in term of water-resistance,adhesion,pencil hardness,the hydrophilic properties and storage modulus.