The Surface Modification Of PGA, PLA, PGLA Fibers And Its Effect On Fibers’ Properties

Biomedical polymer materials were widely used in biological and medical fields. When the polymer materials were in contact with human body permanently or transiently, they can cause the adverse biological reactions, for example, inflammation, carcinogenesis, forming thrombus and so on. The adverse biological reactions were caused by the action of materials surface and biological environment. Surface modification of polymer materials can enhance their biocompatibility.PGA, PLA and PGLA are widely used at home and abroad as biodegradable materials. PGA has a better biocompatibility, but its degradation is too fast to meet the mechanical demand of human body. PLA has a slow degradation to meet the mechanical demand of human body. But its hydrophilic is poor, which is against to the attachment and growth of cells. PGLA shows good application potential in biological and medical fields. However, cell attachment and cell growth on it cannot meet the demand of tissue engineering because of its strong hydrophobic, lack of cell recognition site and so on.This paper is related to surface modification of PGA, PLA and PGLA fibers by alkali treatment, oxidation process and ultrasonic treatment method. NaOH was selected as alkali treatment reagent, while NaCIO, K2Cr2O7and H2O2as oxidation process reagents. Through the contrast of performance of fibers before and after modification, the effects of alkali treatment and its process parameters on the fundamental and degradation performance of fibers were studied. Moreover, the effects of oxidation process, ultrasonic treatment and their process parameters on the fundamental performance of fibers were studied. Meanwhile, the effects of modification methods on biocompatibility of treated fibers were studied by the test of in vitro cytotoxicity. The results indicated that:After alkali treatment, PGA, PLA and PGLA fibers hydrolyzed partially, with molecular chains ruptured. The breaking strength loss of PGA and PGLA fibers were larger, while which of PLA fiber was less. The water contact angle of PGA fiber reduced, improving its hydrophilic. And the water contact angle of PLA and PGLA fibers increased, with their hydrophilic becoming worse. PGA and PGLA fibers had lower melting point, higher crystalline, rougher surface and worse uniformity. PLA fiber had higher melting point, lower crystalline, more surface stripe and larger evenness. The degradation of PGA and PGLA fibers speeded up, while that of PLA fiber changed little. The biocompatibility of PGA, PLA and PGLA fibers were still good with a low cell proliferation rate. As the time of NaOH-treatment increased, the breaking strength of PLA fiber reduced gradually, while the water contact angle increased firstly and then decreased. As the mass fraction of NaOH increased, the breaking strength of PGLA fiber reduced gradually, while the water contact angle increased firstly and then decreased. The time of NaOH-treatment had certain equivalent relations with the mass fraction of NaOH during alkali treatment. The change of treatment process parameters had little effect on the degradation performance of treated fibers, without specific laws.After NaClO-treatment, PGA, PLA and PGLA fibers hydrolyzed partially, with molecular chains ruptured. PGA and PGLA fibers lost much breaking strength with smaller water contact angle, lower crystalline and better hydrophilic. PLA fiber lost little breaking strength with smaller water contact angle, lower crystalline and better hydrophilic. The biocompatibility of PGA, PLA and PGLA fibers were still good with a low cell proliferation rate. As the time of NaClO-treatment or the mass fraction of NaClO increased, the breaking strength of PGA and PGLA fibers reduced gradually, while that of PLA fiber rose and fell modestly. The water contact angle of PGA, PLA and PGLA fibers rose and fell as well.After K2Cr207-treatment, PGA, PLA and PGLA fibers hydrolyzed partially, with molecular chains ruptured. PGA and PGLA fibers lost much breaking strength with larger water contact angle, lower crystalline and worse hydrophilic. PLA fiber lost little breaking strength with smaller water contact angle, lower crystalline and better hydrophilic. The biocompatibility of PGA, PLA and PGLA fibers were still good with a low cell proliferation rate. As the time of K2Cr207-treatment increased, the breaking strength and water contact angle of PGA, PLA and PGLA fibers rose and fell. The change of K2Cr207-treated time had little effect on the fundamental performance of treated fibers, without specific laws.After H2O2-treatment, PGA, PLA and PGLA fibers hydrolyzed partially, with molecular chains ruptured. PGA, PLA and PGLA fibers lost little breaking strength with larger water contact angle, lower crystalline and worse hydrophilic. After H2O2-treatment, The biocompatibility of PGA, PLA and PGLA fibers were still good with a high cell proliferation rate. As the time of H2O2-treatment increased, the breaking strength and water contact angle of PGA, PLA and PGLA fibers rose and fell. The breaking strength of treated fibers changed little, and the water contact angle became larger. The change of H2O2-treated time had little effect on the fundamental performance of treated fibers, without specific laws.After ultrasonic treatment, molecules chains of PGA, PLA and PGLA fibers got shocked, and molecules recombined to new active group. PGA, PLA and PGLA fibers lost little breaking strength with larger water contact angle, lower crystalline and worse hydrophilic.The biocompatibility of PGA, PLA and PGLA fibers were still good with a high cell proliferation rate. As the time of ultrasonic treatment increased, the breaking strength of PGA, PLA and PGLA fibers decreased firstly and then increased, and water contact angle of rose and fell.