發(fā)布時間：2018-09-06 06:38

【摘要】：聚乳酸的韌性差,降解產(chǎn)物呈酸性,缺乏骨結(jié)合力；鎂合金強度高,但降解速率過快,研制各種鎂合金與聚乳酸的復(fù)合材料是解決這些問題的有效途徑。本文對鎂合金絲進行二維編織,利用熱壓成型工藝制備出了鎂合金絲編織結(jié)構(gòu)增強聚乳酸復(fù)合材料,獲得了最佳成型工藝參數(shù),研究了編織角和鎂合金絲體積分數(shù)對復(fù)合材料力學(xué)性能的影響,分析了鎂合金絲表面微弧氧化處理對復(fù)合材料拉伸強度和剪切強度的影響,并對復(fù)合材料在模擬體液中的降解性能進行探索,結(jié)果如下：對比研究了兩種不同鎂合金絲編織結(jié)構(gòu)增強聚乳酸復(fù)合材料的制備過程,確定了鎂合金絲編織增強結(jié)構(gòu)為二維二軸,且結(jié)構(gòu)形式為1×1；在系統(tǒng)研究了熱壓工藝參數(shù)對復(fù)合材料彎曲強度影響的基礎(chǔ)上,獲得了復(fù)合材料的最佳成型工藝,即熱壓溫度165℃C、熱壓壓力2.6MPa和保壓時間20min。編織角和鎂合金絲體積分數(shù)對復(fù)合材料的力學(xué)性能有顯著影響。編織角保持30°不變時,增大鎂合金絲體積分數(shù)(0-12%),復(fù)合材料的拉伸強度、彎曲強度、橫向剪切強度和沖擊韌性增大,鎂合金絲體積分數(shù)為12%時,分別是純聚乳酸的1.6、1.8、1.6和2.8倍；鎂合金絲體積分數(shù)保持10%不變時,增大編織角(15°-60°),復(fù)合材料的拉伸強度和彎曲強度減小,而橫向剪切強度和沖擊功呈現(xiàn)先增大后減小的趨勢,并在45°時達到最大值,分別為75.6MPa和0.23J；通過與鎂合金絲定向增強聚乳酸復(fù)合材料對比研究,發(fā)現(xiàn)采用鎂合金絲編織結(jié)構(gòu)強化有利于改善復(fù)合材料縱向剪切性能。鎂合金絲微弧氧化處理可改善復(fù)合材料中兩組元的界面結(jié)合性能,充分發(fā)揮鎂合金絲的強化作用,編織角30°、鎂合金絲體積分數(shù)12%的復(fù)合材料拉伸強度達到80.4MPa,比鎂合金未微弧氧化的高13.7MPa；模擬體液浸泡4周過程中,純聚乳酸的浸泡液pH值保持下降趨勢,而復(fù)合材料浸泡液pH值先下降,1周左右會有所上升,并在4周時基本保持穩(wěn)定。編織角30°、鎂合金絲體積分數(shù)7%的復(fù)合材料和純聚乳酸降解8周后的剩余彎曲強度分別為56MPa和31MPa,復(fù)合材料彎曲強度降低幅度小。復(fù)合材料中鎂合金絲降解主要集中在微弧氧化陶瓷層膜上,絲材基體腐蝕不明顯,而其聚乳酸組元分子量從5.5萬下降到3.9萬,但高于純聚乳酸(3萬),說明鎂合金絲的存在能緩解聚乳酸的降解。
[Abstract]:The toughness of poly (lactic acid) is poor, the degradation products are acidic and lack of bone adhesion, and magnesium alloy has high strength, but the degradation rate is too fast. It is an effective way to solve these problems by developing various kinds of composite materials of magnesium alloy and polylactic acid. In this paper, two dimensional braiding of magnesium alloy wire was carried out, and the braided structure reinforced poly (lactic acid) composite was prepared by hot pressing process, and the optimum forming process parameters were obtained. The effects of braiding angle and volume fraction of magnesium alloy wire on the mechanical properties of the composites were studied. The effects of micro-arc oxidation on the tensile strength and shear strength of the composites were analyzed. The degradation properties of the composites in simulated body fluid were explored. The results were as follows: the preparation process of two different magnesium alloy wire braided structure reinforced PLA composites was studied. The braided reinforced structure of magnesium alloy wire is determined to be two dimensional biaxial, and the structure form is 1 脳 1. Based on the systematic study of the influence of hot pressing process parameters on the bending strength of the composite, the optimum molding process of the composite is obtained. The hot pressing temperature is 165 鈩，

本文編號：2225550