PVA nanofibers are generally required to be modified because of its poor stability in water. The water stability of PVA nanofibers was improved by heat treatment in this paper. The DSC test results showed that the crystallinity of heat-treated PVA nanofibers at 150°C for 10 min reached the maximum which increased by 12% compared with PVA nanofibers. From the SEM images it was observed that the heat-treated fibers didn’t dissolve in water but showed certain degree of agglutination and swelling. PVA nanofibers were taken as the inner layer of the sandwich structure purification material prepared with the hot pressing technology. The filtering experiments showed that the filtration properties were better when the area density of PVA nanofibers was 2.5 g/m2.
Poly(ε-caprolactone) (PCL)-polystyrene (PS)star-block copolymer with a cross-linked microgel core were synthesized by the combination of atom transfer radical polymerization (ATRP) of St and lipase-catalyzed ring-opening polymerization (ROP) of ε-CL. The characterization of PCL-Br, PCL-PS-Br macroinitiator and PCL-PS Star-block copolymers was detected by GPC and 1H NMR. Results showed that the target star-block copolymers were successfully prepared.
Electrospinning of PVA can be performed from aqueous solution leading to the generation of homogenous nanofiber webs. PVA nanofibers are generally required to be modified because of its poor stability in water. The water stability of PVA nanofibers was improved by heat treatment in this paper. The test results showed that the crystallinity of the PVA nanofibers increases after heat-treatment. The crystallinity which is the largest increased by 12% when they were treated at 150°C for 10 min. The heat-treated fibers don’t dissolve in water and show certain degree of agglutination and swelling. PVA nanofibers were taken as the inner layer of the sandwich structure purification material prepared with the hot pressing technology. The filtering experiment showed that the filtration properties were better when the area density of PVA nanofibers is 2.5g/m2. The filtration efficiency of materials and retention rate of PVA nanofibers decreased after being used for 5 times.
In this paper, metallocene based LLDPE (mLLDPE) extra-fine fiber , which can not be processed by a common solution electrospinning method.was successfully prepared via a melt electrospinning method. First, a self-designed melt electrospinning device was manufctured and it was used to produce mLLDPE fibers . Then LLDPE extra-fine fiber was successfully prepared by addition of viscosity-reducing additive such as wax, and the resulted fiber was charctered by SEM. Last, the optimal parameters for the preparation of mLLDPE fiber was determined. The experimental results show that commercial mLLDPE can hardly be processed to fibers because of its high viscosity. The diameter and morphology of resulted mLLDPE electrospun fibers depend on the electrospinning parameters such as electric field strength and collecting distance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.