本文選題：聚乳酸 + 聚氧化乙烯��； 參考：《鄭州大學(xué)》2017年碩士論文

【摘要】：聚乳酸(PLA)是一種來源于可再生資源的重要的可生物降解結(jié)晶性聚合物。但是PLA的脆性大,限制了它的應(yīng)用范圍。將PLA和低玻璃化轉(zhuǎn)變溫度(Tg)的聚合物共混是改善其韌性的重要手段。聚氧化乙烯(PEO)是一種重要的低Tg聚合物,同時還具有毒性低、生物相容性好的優(yōu)點(diǎn)。因此,PLA/PEO共混體系已得到越來越多的關(guān)注。本論文重點(diǎn)研究了PEO組分的引入對PLA多晶型結(jié)構(gòu)的影響,主要結(jié)果如下:(1)熔融結(jié)晶條件下PEO對PLA多晶型結(jié)構(gòu)影響的研究。通過熔融共混法制備了組分含量分別為(100/0)、(90/10)和(80/20)的PLA/PEO共混物,利用廣角X射線衍射儀(WAXD)研究了等溫熔融結(jié)晶條件下PEO對PLA晶體結(jié)構(gòu)的影響,結(jié)果表明:純PLA在Tc≤110 oC和Tc110 oC結(jié)晶分別形成α′晶α晶。而在PLA/PEO共混物中,WAXD衍射曲線上(110/200)晶面和(203)晶面的衍射峰不隨等溫結(jié)晶溫度Tc的變化而發(fā)生偏移,沒有觀察到明顯的α′晶,表明PEO的存在促進(jìn)了PLA中α晶的形成。接下來,借助差示掃描量熱儀(DSC)研究了PEO對PLA結(jié)晶行為的影響,并利用Avrami模型對其結(jié)晶動力學(xué)進(jìn)行了分析,結(jié)果表明:PEO的引入并沒有明顯改變PLA的Avrami指數(shù),表明PEO沒有影響PLA的結(jié)晶機(jī)理;另一方面,PEO的引入明顯提高了PLA的結(jié)晶速率,這可歸因于共混物Tg和平衡熔點(diǎn)的降低,從而促進(jìn)了PLA分子鏈的運(yùn)動。(2)冷結(jié)晶條件下PEO對PLA多晶型結(jié)構(gòu)影響的研究。通過熔融共混法制備了組分含量分別為(100/0)、(99/1)、(98/2)、(95/5)、(90/10)和(80/20)的PLA/PEO共混物,利用WAXD研究了PEO對PLA等溫冷結(jié)晶晶體結(jié)構(gòu)的影響。結(jié)果表明:純PLA在Tc110 oC冷結(jié)晶時得到的晶體是α′晶,當(dāng)Tc≥110 oC形成α晶;隨著共混物中PEO含量的增大,PLA形成α′晶和α晶的臨界溫度沒有明顯變化,但是α′晶和α晶的2θ角的差值逐漸縮小,當(dāng)PEO含量增大到10%及以上時,已觀察不到明顯的α′晶的存在。另外,還利用WAXD原位研究了在Tc=90 oC冷結(jié)晶PLA及其與PEO的共混物在升溫過程中結(jié)晶結(jié)構(gòu)的演化,結(jié)果表明,純PLA在升溫過程中有明顯的α′晶到α晶的晶型轉(zhuǎn)變,這種轉(zhuǎn)變也存在于(99/1)、(98/2)、(95/5)PLA/PEO共混體系中。
[Abstract]:Polylactic acid (PLA) is a kind of come from renewable resources important biodegradable crystalline polymer. But PLA brittleness limits its scope of application. The PLA and low glass transition temperature (Tg) of the polymer blend is an important means to improve its toughness. Poly ethylene oxide (PEO) is a low Tg polymer is important, but also has low toxicity, good biocompatibility and good. Therefore, PLA/PEO blends has gained more and more attention. This paper focuses on the impact of the introduction of the PEO component of PLA polycrystalline type structure, the main results are as follows: (1) study on the effect of melt crystallization under the condition of PEO on the PLA crystal structure. Prepared by melt blending components respectively (100/0), (90/10) and (80/20) PLA/PEO blends, using the wide angle X - ray diffraction (WAXD) studies the effects of isothermal Melt Crystallization Conditions on the crystal structure of PLA PEO, The results show that the pure PLA crystal form alpha 'alpha crystal respectively in Tc and Tc110 less than 110 oC. The crystallization of oC in PLA/PEO blends, WAXD diffraction curve (110/200) and (203) crystal plane diffraction peak did not change with the isothermal crystallization temperature of Tc and shift, not observed in alpha' crystal obviously, indicated that PEO promoted the formation of a crystal in PLA. Then, by means of differential scanning calorimetry (DSC) to study the effects of PEO on the crystallization behavior of PLA, and the crystallization kinetics was analyzed using the Avrami model results show that the introduction of PEO and PLA did not significantly alter the Avrami index PEO, that does not affect the crystallization mechanism of PLA; on the other hand, the introduction of PEO can significantly improve the crystallization rate of PLA decreased, which could be attributed to the blend of Tg and the equilibrium melting point, thus promoting the movement of PLA molecular chain. (2) study on the influence of cold crystallization conditions of PEO polycrystalline PLA type structure. 閫氳繃鐔旇瀺鍏辨販娉曞埗澶囦簡緇勫垎鍚噺鍒嗗埆涓，

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