Sova N. Scientific bases for technologies of structural modified polymeric materials and composites for multifunctional applications

Thesis is dedicated to the solution of important technical and scientific problem of the development innovation polymer materials with programmable structure and properties. Technology development for structure modified polymer materials and composites for manufacturing of polymer articles with predictable or programmable properties for modern industrial usage. Modification of polymer properties by interaction with low molecular weight substances was studied as modification techniques for polyester copolymer family – PET, PETG and PCTG and for copolymers and homopolymers of PLA. First investigated new properties for interaction of PETG, PCTG and PET with low molecular weight acetic acid esters, like ethyl and butyl acetate. Sorption and desorption kinetics is investigated for different types of polymers, polymer blends and composites in liquid and vapor phase. First discovered that desorption of ethyl acetate in polyester is not complete under ambient condition witch results in stable concentration of low molecular weight ester under prolonged period of time in range from 3,5 to 5,5 %. Incomplete desorption is a result of strong intermolecular forces based on hydrogen bonds. Further study was found that polyester materials with incomplete desorption of low molecular weight ester can be processed further by different techniques like extrusion, injection molding, orientation drawing. Single direction orientation drawing was used for polyesters modified by sorption of ethyl acetate in different conditions. High level of stretching ratio was achieved for PETG and PCTG samples with increased value of tensile strength. Low temperature stretching of PET and PCTG is possible for samples which was modified with ethyl acetate. Modification of PP and PP copolymer with Iodine in vapor phase was studied for different samples. Sorption and desorption kinetics was recorded together with materials properties changes. First developed technology for FFF additive manufacturing for creation of foamed article with application of incomplete desorption of EA in PETG which was applied for PETG filament in solid state way. Articles created with new technology having low bulk density and high impact strength. High temperature resistant foamed article was created with application of PET and PET/PETG blend as starting material for solid state filament modification. Modification of PETG and PET with supercritical CO2 was carried out with utilization of ethyl acetate and solid polyester oligomer additive. Reduction of sorption time was observer for modified samples. Low molecular weight ester modified polyester undergoes crystallization during ester sorption. Combined process of low molecular weight ester and supercritical CO2 modification is investigated for PETG and PCTG, significant CO2 sorption intensification is observed. Composite materials based on PLA and calcium carbonate filler with high filling ratio and high impact properties was created based on polyester oligomer modification techniques. Technology of high thermal resistant PET and PETG particle foam was development with application of chemical blowing and low molecular weight oligomer modification. First developed new manufacturing technology for additive manufacturing of nonwoven filtering materials from PLA and PP from bicomponent polymer blend. Semi-finished article created by addition manufacturing was solvent treated for partial dissolution and extraction for one of the blend components. Electrically conductive and flame retardant materials based on modified TPU was created and applied for additive manufacturing of radio wave interactive material and custom shape ESD materials. First developed new additive manufacturing technology of liquid consumables based on PVC plastisols and organosols. Technology allows creation of extremely soft and elastic articles from liquid PVC plastisol with conversion of widely used FFF equipment. New foaming technology for PET and PETG was developed by application of pyromellitic dianhydride (PMDA) hydrolysis products. Masterbatch of PMDA was solid state hydrolyzed and used in pellet form for foaming process which was carried out in hot air flow. High temperature resistant PET particle foam was created and evaluated for promising application in novel composite materials.