以靜電紡絲製備聚苯噁唑-聚乳酸分子複合材料

Electrospun Molecular Composites of Poly(p-phenylenebenzobisoxazole)-Poly(L-lactic acid)

盧 毅(Yi Lu)

指導教授 ： 陳建中

臺北醫學大學/口腔醫學院/生醫材料暨工程研究所/碩士(2009年)

摘要

本研究主要目的在利用靜電紡絲之方式，將poly(p-phenylene benzo-bisoxazole) (PBO)與poly(L-lactic acid) (PLLA)製備成分子複合薄膜。先將PBO及PLLA分別以TFA/MSA (volume rate: 1/1)和DCM溶劑，配製成0.8 w/v %和10 w/v %成膜原液，經單一針筒混合式靜電紡絲、雙針筒模頭混合式靜電紡絲之方式與乾式成膜製備成PBO-PLLA薄膜，水洗12小時去除溶劑後乾燥，並利用熱重分析儀 (TGA)觀察薄膜熱穩定性和燒結殘餘量，接續以溫度調幅式微差掃瞄熱卡儀 (TMDSC)、X光繞射儀 (XRD)、掃描式電子顯微鏡 (SEM)及正弦波震盪黏度儀，分析薄膜之玻璃轉移溫度 (Tg)、結晶度 (weight fractional crystallinities, Xc, %)、結晶結構、表面形態以及黏度差異。結果顯示，以單一針筒混合式靜電紡絲製備薄膜，其熱裂解溫度在358 ℃，隨著PBO固含量從0 %~10 %，薄膜的燒結後殘餘量由1.0 wt %升高至5.6 wt %，Tg則介於52.2~56.0 ℃，Xc介於41.32~56.10 %，結晶形態不明顯，表面纖維直徑由4.89±0.76 ?慆下降至0.54±0.15 ?慆，而以利用雙針筒模頭混合式靜電紡絲PBO-PLLA薄膜，熱裂解溫度為358 ℃，PBO固體含量從0 %~10 %，薄膜燒結後殘餘量由1.21 wt %提升至10.78 wt %，Tg則介於 52.5 ℃至57.4 ℃，Xc介於45.14 % ~49.97 % 之間，其結晶強度於471上升至1745，表面纖維直徑由1.02±0.28 ?慆下降至0.58±0.30 ?慆，薄膜於溶解後進行黏度分析，其值為0.62、0.39、0.37、0.40、0.30及0.30 cP，另外，乾式成膜燒結後殘餘量由1.04 wt %增加至11.87 wt %，Tg則介於53.30 ℃至55.95 ℃之間，Xc從39 %上升至54 %，亦結晶形態在2??=17.15˚產生結晶，結晶強度622提高至1715，薄膜經溶劑溶解後其黏度為0.75、0.45、0.46、0.45、0.45及0.38。以單一針筒混合式靜電紡絲製備薄膜，其添加PBO固體含量對於纖維殘留量，Tg、Xc及結晶強度無較明顯之影響，纖維直徑則逐漸變小，而雙針筒模頭混合式靜電紡絲薄膜卻因電紡過程中PBO溶劑未及時揮發，而將PLLA裂解，導致薄膜Tg略為下降，Xc無明顯之提升，分子量則下降，導致纖維直徑則逐漸變小。乾式成膜之方式其混合時間較短並馬上水洗，減少酸性溶劑的影響，因此對Tg而言有提高之幫助，於Xc則逐漸上升。由本研究可得知利用單一針筒混合式靜電紡絲及雙針筒混合式靜電紡絲製備PBO-PLLA纖維薄膜，其具有良好熱穩定性及較低結晶度之薄膜。

關鍵字

分子複合材料 ； 靜電紡絲 ； 乾式成膜 ； 聚苯噁唑 ； 聚乳酸

並列摘要

The objective of this study is to fabricate molecular composite membranes of poly(p-phenylenebenzo-bisoxazole) (PBO) and poly(L-lactic acid) (PLLA) by electrospinning technique and dry-casting. Firstly, PBO and PLLA were dissolved separately in TFA/MSA (volume ratio: 5/5) and DCM as 0.8 w/v % and 10 w/v % solutions, respectively, then composite membranes were fabricated by electrospinning technique and dry-casting. Membranes were subsequently washed in deionized water to remove the solvents and dried in the oven. Glass transition temperature (Tg), weight fractional crystallinities (Xc, %), crystal structure and surface morphology of these membranes were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The TGA data showed the percentage residue weight of sintered electrospun membranes were increased from 1.21 wt% to 10.78 wt %. The glass transition temperatures were decreased from 60.6 ℃ to 51.5 ℃ and the average diameter of fibers was decreased from 1.02±0.3 ?慆 to 0.58±0.3 ?慆. The values of Xc were between 12.2 % and 27.0 %, and the crystal diffraction intensity was weak. On the other hand, the glass transition temperatures of cast membranes were increased from 55.5 ℃ to 58.2 ℃. The Xc were also increased from 5.1 % to 35.9 %. However, it is still considered a poor crystalline structure by very weak diffraction pattern. The thermal stability of PLLA was not affected with adding PBO. Different from the case of electrospun membrane, the residue weight percentage of sintered cast membranes were remain constant even with increased content of PBO. This might due to the uneven mixing of solutions. Tg of cast film membranes was higher than that of pure PLLA, suggesting some degree of molecular level mixing between PLLA and PBO. On the other hand, this was not the case for electrospun membrane, probably due to the mixing did not take place by very limited contact time between two solution. The Xc of both membranes were far lower than perfectly crystalline PLLA (93.7 J/g), suggesting very poor crystalline structure. These electrospun PBO-PLLA membranes showed lower crystalline structure which might be desirable for some special medical applications when faster degradation is needed.

並列關鍵字

molecular composite, ； electrospinning ； dry-cast ； PBO ； PLLA

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