不同Paraffin含量對PE-b-PEG/Paraffin崁段共聚物混摻之熱行為、結晶動力學及奈米自組裝形態結構之研究

Effects of paraffin content on the thermal property, isothermal crystallization kinetic, nanotemplet assemble and morphology behavior of polyethylene-block-poly(ethylene glycol)/paraffin binary blends

黃晴蘭(Ching-Lan Huang)

指導教授 ： 陳建宏

崑山科技大學/工程學院/綠色材料研究所/碩士(2010年)

https://doi.org/10.6828/KSU.2010.00075

摘要

本論文主要為探討利用掃描式熱卡分析儀(DSC)、廣角X-光繞射儀(WAXD)、偏光顯微鏡(POM)、穿透式電子顯微鏡(TEM)以及動態廣角小角X光散射儀進行PE-b-PEG/Paraffin崁段共聚物混摻之熱行為、結晶動力學及奈米自組裝形態結構之研究。DSC結果得知PE-b-PEG/Paraffin混摻共聚物中之PEGb、Paraffin、PEb的熔點分別為32、58、103oC。隨Paraffin含量之增加，PEb的熔點呈現些微下降；PEGb、PEb的熔融峰隨之下降。相對的PEGb、Paraffin、PEb的結晶化溫度分別為18、51、95oC。並且混摻中PEGb、Paraffin、PEb各成分的結晶行為各自獨立形成三重結晶化峰。相對的由WAXD結果得知PE-b-PEG/Paraffin混摻的結晶結構呈現一般Paraffin及PEb之(110)、(200)結晶面及PEGb的(120)、(032)結晶面，並且PE-b-PEG/Paraffin混摻的結晶結構在不同混摻條件下緊隨成份比呈現單調的變化。另一方面，由穿透式電子顯微鏡(TEM)觀測中可以明顯看出不同Paraffin含量下的PE-b-PEG/Paraffin共聚混摻物形態幾乎為層狀形態結構(lamellar morphology)並且其長週期或層狀之間距大約為9.6-12.3nm。並且隨Paraffin含量的增加，PE-b-PEG/Paraffin混摻共聚物中的PE-b-PEG層狀結構的長週期或層狀之間距幾乎不變，但在照片中可發現有大量的Paraffin貫穿在PE-b-PEG層狀結構的中間，證明PE-b-PEG/Paraffin混摻共聚物系統為一相分離結構。
在動態廣角-小角X-光散射(WAXS-SAXS)分析中發現在不同Paraffin含量下， PE-b-PEG/Paraffin二崁段共聚物混摻物的SAXS散射圖中發現隨Paraffin含量之增加，在升溫過程中PE-b-PEG/Paraffin二崁段共聚物混摻物中的PE-b-PEG的SAXS圖將呈現層狀(低於PEG熔點以下)、柱狀(介在PEG與PE熔點之間)、非晶層狀或球狀形態結構(高於PE熔點以上)的轉變；相對在降溫過程中呈現可逆的行為。其中PE-b-PEG/Paraffin二崁段共聚物混摻物的主要散射峰位置(q值)一直保持在約0.052Å-1(層狀結構的長週期約為12.08nm)，這現象表示隨Paraffin含量之增加對PE-b-PEG/Paraffin二崁段共聚物混摻物中的PE-b-PEG二崁段共聚物的形態結構並無明顯的影響，證明Paraffin含量在PE-b-PEG/Paraffin二崁段共聚物混摻物中呈現相分離行為。另一方面，在SAXS散射圖中q值約為0.17Å-1(Paraffin的長週期約為3.7nm)意味為Paraffin結構的散射峰的SAXS散射強度隨Paraffin含量之增加而明顯增加，表示PE-b-PEG/Paraffin二崁段共聚物混摻物中Paraffin的散射含量增加。並比對於純Paraffin的SAXS圖可確認此散射峰為Paraffin的結構形態因子。
另一方面，隨Paraffin含量之增加，PE-b-PEG/Paraffin二崁段共聚物混摻物的WAXS散射圖中發現在較低溫度下(低於PEG-b熔點約60oC)有二組WAXS散射峰：分別q值約為1.5Å-1及1.68Å-1歸因於PEb之(110)、(200)結晶面；以及q值約為1.34Å-1及1.62Å-1歸因於PEGb的(120)、(032)結晶面，意味PE-b-PEG/Paraffin二崁段共聚物混摻物在低溫區域為雙結晶性結構。其中PEGb的(120)、(032)結晶面的散射強度隨溫度接近60oC時幾乎消失(表示PEG-b的結晶結構熔融瓦解)。因此當溫度介在60oC-105 oC (當PEG-b熔融以後)，PE-b-PEG二崁段共聚物之WAXS散射圖譜僅呈現PEb之(110)、(200)結晶面。最後當溫度接近於105 oC (接近PE-b熔點)，PE-b-PEG二崁段共聚物之PE-b開始瓦解，當溫度高於105 oC以上WAXS散射圖譜僅呈現非晶的訊息，意味純PE-b-PEG二崁段共聚物形態結構在105 oC以上轉變為非晶的結構。另一方面，隨Paraffin含量之增加，在WAXS散射圖中產生明顯的改變，當Paraffin含量之增加在WAXS散射圖中PEG含量的強度明顯減少，尤其當50/50wt% 之PE-b-PEG/Paraffin二崁段共聚物混摻物中的WAXS散射圖僅呈現相當微弱的結晶強度，意味在50/50wt%的混摻比下最會抑制PE-b-PEG/Paraffin二崁段共聚物混摻物中的結晶化行為。最後當Paraffin含量超過50/50wt% 則PE-b-PEG/Paraffin二崁段共聚物混摻物中的WAXS散射圖將呈現Paraffin的結晶結構。

關鍵字

PE-b-PEG/Paraffin混摻共聚物 ； 結晶動力學 ； 奈米自組裝 ； 形態結構變化

並列摘要

In this work, we provided insights into effect of paraffin content and isothermal temperature on the thermal properties, isothermal crystallization kinetic, nanotemplet assembled and morpholries transition behaviors of polyethylene-block-poly(ethylene glycol)/paraffin (PE-b-PEG/PAF) binary blends by means of differential scanning calorimetry (DSC), wide-angle X-ray diffractions (WAXD), transmission electron microscope (TEM), polarized optical microscopy (POM), and in situ small-angle and wide-angle X-ray scattering (SAXS and WAXS). Herein, the melting temperature of PEGb、Paraffin、PEb is 32, 53, and 103oC, respectively. However, the isothermal crystallization mechanisms of PE-block and paraffin, PEG-block in PE-b-PEG/PAF binary blends preceded by unconfined and confined crystallizations, respectively, to form the interlamellar to the breakout lamellar morphology with increased paraffin content. It maybe the paraffin was dry brushed between PE-b-PEG interlamellar domains and preceded the multi-crystallization behaviors during isothermal crystallization at various Tcs. The characteristic parameters of the Avrami exponent; n-bPE, and n-bPEG are ca. 2.0, implying it hinted a thermal nucleation process followed by the two-dimensional growth or self-assemble. While that of n-PAF is ca. 2.2-2.8 attributed to hint a thermal nucleation process followed by two- to three-dimensional growth depended on paraffin content. Although the microstructures of PE-b-PEG/PAF blends combined the monoclinic crystal of PEG and orthorhombic crystal of PE together and independent up the paraffin contents. The results of TEM and SAXS indicated that the effects of paraffine content on the morphology of the PE-b-PEG/Paraffin binary blend present the lamellar structure, the long-perior of the lamellar structure is about 9.6-12.3nm, which independent of paraffine content. The result indicated that the morphology of the PE-b-PEG/Paraffin binary blend was a macro-phase separation system.
In the results of in situ SAXS-WAXS, however during heating cycle, the SAXS profile of pure PE-b-PEG indicated morphology transition; crystalline lamella (belower than melting temperature of block-PEG), cylinder (temperature between melting points of block PEG and PE), and amorphase lamella (higher than melting point of PE). On the other hand, the SAXS profile of PE-b-PEG/Paraffin binary blend presented another morphology transition; crystalline lamella (belower than melting temperature of block-PEG), cylinder (temperature between melting points of block PEG and PE), and amorphase sphere phases (higher than melting point of PE) during heating cycle. However, the reversible of the morphology transition was observed in cooling cycle. The SAXS profile of PE-b-PEG/Paraffin binary blend presented that the q value of the primary scattering peak of PE-b-PEG diblock copolymer is ca. 0.052Å-1, which means the average thickness of interlamellar morphology is ca. 12.08nm, whereas, the q value of the scattering peak of paraffin is ca. 0.17Å-1, which means the average thickness of interlamellar morphology is ca. 3.7nm. However, the q values of primary scattering peak of PE-b-PEG diblock copolymer and scattering peak of paraffin independent, while the intensities of that dependent of paraffine content provided that the PE-b-PEG/Paraffin binary blend was a macro-phase separation system.
Moreover, The WAXS profiles indicated that the combined the scattering peaks at q values at 1.5 and 1.68Å-1 attributed to crystal planes (110) and (200) of crystalline block PE and that at 1.34 and 1.62Å-1 attributed to crystal planes (120) and (032) of crystalline block PEG together at temperature belower than meltinf point of block PEG. The crystal planes (120) and (032) of crystalline block PEG decreased as temperature around 60oC, and the crystal planes (110) and (200) of crystalline block PE also melting as temperature rised to 105oC, therefore, we obtented a full amorphase phase at temperature above 105oC. The WAXS profile changed remarkable with paraffine content, expecially, WAXS profile showed a near paraffine pattem at over 50wt% paraffine maybe due to paraffine and block PE acted as an effectively confined agent role for block PEG during both heating and crystallization.

並列關鍵字

PE-b-PEG/PAF binary blends ； isothermal crystallization kinetic ； nanotemplet assembled ； and morpholries transition

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