Study On The Preparation And Properties Of Natural Polymer Fluids

In this paper,natural polymers such as chitosan and cellulose are taken as the research objects.Firstly,graft modification is carried out on the surface of the polymer,and then polymer with liquid-like behavior and controllable structure are prepared through ion exchange and acid-base reaction.The morphological and rheological behaviors of the as-prepared fluids were investigated with two different chemical bonding methods and surface graft densities.The rheological behavior of polymer fluids and their performance in organic blends were investigated.The ion-exchanged liquid-like chitosan with excellent performance can be successfully prepared by ion exchanging method,which has fluidity at room temperature,good water solubility,hygroscopicity,moisture retention,and antibacterial property,but it is almost insoluble in organic solvents.This is very different from the previous liquid-like hybrid inorganic particles.The reaction conditions required for the preparation of the fluids in the method are mild,and they are practical for natural polymers containing hydroxyl groups,and are environmentally friendly and non-polluting.Ion-bonded chitosan fluids can be dissolved in neutral water,and fabrics coated with chitosan fluids have good moisture retention properties,and they are expected to be widely used in wound healing antibacterial dressing materials in the future.The covalently bonded liquid-like chitosan were obtained by acid-base reaction.The test results show that high-performance polymer fluids can be successfully prepared by this method.The covalent-bonded chitosan fluids prepared by the method have greatly improved dissolution performance,are soluble in water and general organic solvents,have fluidity above 26 ~oC,and exhibit solid elasticity below 26 ~oC.It shows a clear solid-liquid transition.Through the study of its crystallization properties,it was found that grafted polyoxyethylene ether tertiary amines can induce chitosan to generate spherulites under appropriate conditions,while impurities and external stress can have a significant effect on the crystal morphology of chitosan.The covalently bonded liquid-like microcrystalline cellulose was obtained by acid-base reaction.The test results showed that a high polymer fluid with excellent dissolution performance and good fluidity can be successfully prepared by this method.By comparing the crystallization behavior of liquid-like microcrystalline cellulose and covalently bonded liquid-like chitosan,microcrystalline cellulose fluids with multiple grafting sites were found to be unable to generate spherulites under appropriate conditions.It shows that excessive graft sites destroy the regularity of the natural polymer molecular chain,thus destroying the crystallization performance.The performance of microcrystalline cellulose fluid/polylactic acid composite electrospun fiber was studied and it was found that the increase in the proportion of microcrystalline cellulose fluid can effectively increase the toughness of polylactic acid fiber.Within a certain range,it can improve the polylactic acid.The strength of the fiber and the thermal shrinkage of the composite fiber at a high temperature of 190°C.are also suppressed because the microcrystalline cellulose fluid has good compatibility with the polylactic acid,meanwhile,it retains the inherent special properties of the microcrystalline cellulose,making the static electricity Spinning composite fibers have improved properties.