No abstract

No abstract

No abstract

To improve the hemocompatibility of the biodegradable medical poly(ether-ester-urethane) (PEEU), containing uniform-size aliphatic hard segments that was prepared in our lab, a copolymer containing phosphorylcholine (PC) groups was blended with the PEEU. The PC-copolymer of poly(MPC-co-EHMA) (PMEH) was first obtained by copolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-ethylhexyl methacrylate (EHMA), and then dissolved in mixed solvent of ethanol/chloroform to obtain a homogeneous solution. The composite films (PMPU) with varying PMEH content were prepared by solvent evaporation method. The physicochemical properties of the composite films with varying PMEH content were researched. The PMPU films exhibited higher thermal stability than that of the pure PEEU film. With the PMEH content increasing from 5 to 20 wt%, the PMPU films also possessed satisfied tensile properties with ultimate stress of 22.9–15.8 MPa and strain at break of 925–820%. The surface and bulk hydrophilicity of the films were improved after incorporation of PMEH. In vitro degradation studies indicated that the degradation rate increased with PMEH content, and it took 12–24 days for composite films to become fragments. The protein adsorption and platelet-rich plasma contact tests were adapted to evaluate the surface hemocompatibility of the composite films. It was found that the amount of adsorbed protein and adherent platelet on the surface decreased significantly, and almost no activated platelets were observed when PMEH content was above 5 wt%, which manifested good surface hemocompatibility. Due to the biodegradability, acceptable tensile properties and good surface hemocompatibility, the composites can be expected to be applied in blood-contacting implant materials.

Synthetic fibers have characteristics that plant fibers do not have, such as water resistance, chemical resistance, heat resistance, and thermal stability. If mixed with plant fibers and applied to make air filter paper, then the required properties of paper could be obtained. Two kinds of synthetic fiber, polypropylene (PP) and polyester (PET), were mixed with softwood pulp to make air filter base paper. The effects of the mixing ratio, the beating degree of softwood pulp, the variety and addition amount of reinforcing agents, and the process of pressing and drying on the properties of base paper were explored. Samples were found to meet the requirements of the physical properties and porosity of the filter paper base paper at the same time when the mixing ratio of synthetic fiber and plant fiber was 20/80, the beating degree of softwood pulp was 22 °SR, and the added amount of cationic polyacrylamide (CPAM) was 0.06%. The PP fiber fell off easily from the page, but PET fiber did not. The addition of PET fiber increased the porosity, tear index, and folding endurance of the paper. In sum, PET fiber was more suitable for making air filter paper than PP fiber.