Formation Of Polyurethane/Poly (N-Isopropyl Acrylamide) Membrane And Analysis Of Its Moisture Permeability Based On Temperature

It has been taken for granted that smart polymer materials, as a rookie, have brought about significant changes in the field of materials. Scientific research workers all over the world have beening researching and developing the new materials. At present, smart polymer materials have a wide range of applications in advanced technology, national defense, national economic and other fields and become a vibrant new fields. The paper do a preliminary research and representation to the permeability of PU and PU/PNIPAAm with different material ratio.First, we chose HMDI, PTMG and small molecule chain extension agent BDO as the main raw material to get linear shape memory polyurethane in a certain experimental conditions system. HMDI, as aliphatic diisocyanate without benzene ring, has less toxic and is harder to become yellow. PTMG can be used to synthesis SMPU with low melting point and has very good biocompatibility. PNIPAAm’s critical temperature is relatively close to the human body temperature, so we chose it as another part of the smart polymer materials.Secondly, we chose the best synthesis process, the best synthesis method and other conditions.We also used FTIR, WAXD, DSC, the hydrophilic test, water absorption test, the moisture permeability and other related analysis tests to research its properties.Finally, it was found that its crystal melting temperature was lower and close to the comfortable temperature range through the analysis for the PU synthesised by HMDI and PTMG. The material was also hard to become yellow, and the synthetic process was easy to control. In one word, it can satisfy the needs of the compound. Through to the PU/PNIPAAm composite membrane related tests, it was found that with the addition of PNIPAAm the trigger temperature, contact angle, water absorption and mechanical properties had changed; PU/PNIPAAm composite membrane trigger temperature increased, the contact angle had become smaller, water absorption was larger, elongation at break decreased; we also found these conditions such as hard segment content, PNIPAAm content, thickness, different film temperature and different film processing technology had a major influence on the moisture permeability. When the other conditions were in certain circumstances, thickness increases, the permeability reduced; phase separation degree was more apparent and permeability increased with hard segment content increasing; composite membrane temperature sensitivity was obvious and moisture permeability increased markedly especially when the temperature was above33℃; membrane forming in wet had more and bigger pore, moisture permeability was higher than those in dry; moisture transmission decreased with the increasing of forming temperature.