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Polylactic acid (PLA) has good biocompatibility, biodegradable, absorbable and non-toxic characteristics of the final product carbon dioxide and water out of the body through the body's metabolism and respiration and circulation, has been widely used in medical surgical sutures , temporary stents, bone repair material, drug controlled release carrier and tissue engineering and other fields. By controlling the molecular weight of the polylactic acid to adjust its degradation rate and therefore the molecular weight directly determine its direction of application as a medical material. The microfiber diameter of electrospinning technology obtained achieve the nanometer level, the fiber surface area, high porosity, etc., can be used as scaffolds for tissue engineering, drug delivery and controlled release carrier material and wound dressing, in many areas There is huge potential uses. In this paper, by ring-opening polymerization preparation of poly (lactic acid), to study the various influencing factors, determine the synthesis of optimum conditions; changing the reactor to solve the blocking problem in the reaction process; integrated purified lactide, to control the polymerization reaction conditions for the realization of controllable molecular weight of the target product, to generate a suitable electrostatic spinning conditions, the desired molecular weight of the polylactic acid. Electrostatic spinning method polylactic acid nanofibers, fiber morphology using scanning electron microscopy, are discussed in detail polylactic acid fiber material with the influencing factors. It was found that the concentration and the solvent is the most important factors that affect the fiber morphology. Compared with methylene chloride, acetone, N, N-dimethyl formamide is electro-spinning the polylactic acid is preferable solvent, the fiber diameter of up to 500 nm or less. Concentration, fiber diameter wider and smoother surface; voltage increases, the fiber diameter thinning; polar distance increases, the jet trickle stretch fully differentiated, tend to form more refined fiber; flow rate increases, The increased fiber spider silk phenomenon, fiber becomes rough. BSA bovine serum albumin as the protein model, polylactic acid as carrier material blends obtained spinning solution electrospinning. By comparing the embedded protein fiber, the the blank release properties of the fiber protein adsorption study the initial protein concentration, protein content release properties. It was found that the protein release rate of the entrapped protein fiber more slowly, because of its protein parcel into the interior of the fiber, protein penetration from the inside of the bracket to release more difficult. Entrapped protein fiber membrane materials are better able to play a controlled release effect, thus we can conclude that: the permeation speed of the target drug is adjusted by changing the morphology of the fiber, to control the density of the pores in the fiber structure, so as to achieve effective to control drug release purposes.
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