Poly Thf Ether Glycol Polyurethane Elastomer Structure - Abrasion Resistance Study Of The Relationship

Under the specific process condition and thermal history, a series of elastomer samples, MDI or NDI or PPDI reacting with different diols (as the extenders) to form the hard segments, PTMEG1000 or PTMEG2000 or PTMEG3000 as the soft segments, are prepared with the bulk casting process. The mechanical property and structure of these samples were characterized by Instron, DMA, DSC, IR, SEM, TEM in order to study the relationship between structure and mechanical property. The abrasion-resistant property of these samples is appraised thoroughly by Akron abrader. The abrasion behavior and the relationship between structure and abrasion-resistant in the process of abrasion are revealed. The morphology of abrasion surface and the mechanism of abrasion breaking are investigated by TEM, SEM. The conclusions are as follows:1. In same molecule weight of soft segment, the abrasion -resistant property increases as the hard segment content increases. The structure of the extender affects the modulus of hard domain therefore affecting the abrasion-resistant of the material. When abrasion angle increases, the abrasion quantity increases.2. The morphology of samples in abrasion process is characterized by TEM and SEM. The micro-crackle and congregation region of micro-crackle are found in surface and sub-surface. At the same time, the breaking pattern of chemical bond in abrasion process is approved with IR. The breaking happens in C-N bond that connects soft segment and hard segment, while the soft segment peeling off as dust particles.3. The mechanism of the material's breaking mechanics is proposed.CD In abrasion process, the material behaves according to the theory of breaking crackle and the theory of composite material. The plastic phase of hard segment restrains crackle growing, expending and congregating. The soft segment phase, the hard segment phase and the intermediate region have their respective moduli.(2) The abrasion process destroys the phase separation of the material and causes phase mixing to some extend.(3) When the abrasion force and compression force co-operate on the surface of material to form the 45 degree shear crackle. The shear crackle further forms the congregation point of stress to accelerate the abrasion and form plough ditch.?The congregation regions of micro-crackles are formed in sub-surface of the material. The abrasion is the peeling off from surface molecule, sub-surface molecule to inter layer of the material .(5) The abrasion is the process of the molecule link breaking. The molecule-link breaking in abrasion process mainly happens in the chemical bond(C-N) between the soft segment and hard segment . After the bond breaking, the soft segment peels off as dust particles.4. The tensile strength and abrasion-resistant property in the system of NDI/PTMEG is better than that in the system of MDI/PTMEG. However the tear strength and dynamic property in the system of NDI/PTMEG is better.