Papers by Author: Hai Ning Lv

Abstract: The purpose of this work was to produce nanocomposites of polylactic acid with oph-POSS (octaphenyl-Polyhedral Oligomeric Silsesquioxanes)-based biodegradable polyester and study morphology, thermal stability and degradation property. Oph-POSS was synthesized via limited-hydrolytic condensation of phenyl trimethoxysilane catalyzed by tetramethylammonium hydroxide. By adding different mass fractions of oph-POSS into the PLA matrix, oph-POSS/PLA nanocomposites were successfully prepared by the solution casting method using chloroform as solvent. SEM(scanning electron microscopy) observations indicated that oph-POSS were homogeneously dispersed in the PLA matrix. The biodegradation rate of oph-POSS/PLA composites was higher than that of neat PLA, moreover, the degradations of neat PLA and oph-POSS/PLA composites underwent the surface erosion mechanism. It was found that the existence of oph-POSS enhanced thermal stability slightly of nanocomposites relative to neat PLA; however, the thermal degradation mechanism of PLA remained unchanged.

Abstract: Microporous membranes were prepared by immersion precipitation phase inversion method from the semi-interpenetrating polymer network (semi-IPN) of shape memory polyurethane (SMPU) and poly (N-isopropylacrylamide) (PNIPAM). The influence of material compostion and preparation procedure on the morphology of membranes such as pore structure and porosity was investigated by methods including Fourier-transform infrared (FT-IR) spectroscopy and scanning electronic microscopy (SEM). Both sponge-like structure and large-pore structure were found in the membranes. The introduction of PNIPAM content in the semi-IPN promotes the formation of large-pore structures and increases the porosity of membranes, due to the improvement of water diffusion into the casting solution. We also found that by increasing the temperature of coagulation bath and the concentration of DMF in the coagulation solution, the formation of large pores could be impeded, and membranes with more sponge-like structure could be prepared.

Abstract: In order to improve the shrinkage resistance of wool fabrics, a new method that combine ionic liquid and chitosan was researched in this paper. Wool fabric was first pretreated with 1 - butyl - 3 - methyl bromination imidazole([Bmim]Br）, and subsequently was treated with chitosan. Pretreatment temperature and time, and chitosan concentration of post-treatment were studied in this paper. Results showed that wool fabrics treated with [Bmim]Br at 80°C for 2 hours and post-treated in 1.0% chitosan acetic acid solution exhibit good shrinkage resistance. In addition, SEM images of ionic liquid treated wool fiber indicates that the scales have been destroyed, and the surface is covered with a layer of film after post-treated with chitosan.

Abstract: Reactive dyes have been widely used in the dyeing of bright colourful silk fabrics. The discoloration and degradation of Reactive Red K-2G in waste water were discussed in this paper. A new heterogeneous photocatalyst named loading phthalocyanine sulfonic iron fibers (FePcS-F) was prepared by phthalocyanine sulfonic Iron supported by modified cellulose fibers in acidic condition. The photocatalytic degradation of Reactive Red K-2G was characterized by discoloration rate to evaluate the effect of catalyst dosage, catalyst loading (CFePcS-F) and solution pH. The results proved that increasing catalyst dosage and CFePcS-F significantly accelerated the dye degradation. FePcS-F catalyst showed higher photocatalytic activity when the solution’s pH value is equal to or less than 6.0, compared to alkaline medium.

Abstract: Needle punching geotextile composites are composed of polypropylene woven fabrics and nonwovens, which has lower strength than that of the original woven fabrics because of the damaging effects by needles during the bonding process. In order to compensate for this shortage, a new geotextile composite was developed using adhesive as bonding media, temperature for controlling adhesive bonding effects. So temperature is the most important factor influencing the composites. With the purpose of researching temperature effects on the performance of polypropylene woven fabrics (single layer of the geotextile composite), a series of tests were carried out and then analyzed. The results show that with the increment of temperature, the shrinkage rate of polypropylene woven fabrics increased continuously. On the other hand, the strength firstly rise with the temperature and then decreased when temperature is over 130°C. Conclusions got in the paper are good references for the development of a new kind of water-insoluble adhesive and adhesive bonded nonwoven geotextile composite.

Abstract: poly(N-isopropylacrylamide) (PNIPPAm) is a thermally sensitive polymeric material which exhibits large volume transition at temperatures around its lower critical solution temperature (LCST). To get a thermosensitive semi-Interpenetrating Polymer Networks(semi-IPNs), N- isopropylacrylamide (NIPPAm) was dispersed and synthesized with different crosslinking agent amount in thermoplastic polyurethane(TPU) solution. The resulting films were characterized in terms of swelling ration, surface contact angle, and scanning electron micrograph (SEM). The results showed that filming medium has great affect on the structure and swelling of PU/PNIPPAm composite film and the amount of crosslinking agent influents the miscibility of PU and PNIPPAm. Ethanol as filming medium makes the phase separation behavior of PNIPPAm insignificant in the films.