分支狀PET的結晶行為以及其對耐候性的影響之研究

聚對苯二甲酸乙二酯(PET)薄膜被應用在光電元件中的基材上，但是在使用壽命上卻略顯不足，因此我們希望在合成時，導入三官能基的單體讓PET產生些微分支狀和提升分子量，以增加它的耐候性。在這個研究中，我們希望去了解產生分支後的PET，它的結晶和熔化行為以及結晶微結構的變化；因為分子鏈段活動力下降，分支後的PET之結晶速率會降低許多，在DSC測量中，再結晶的情況也會因為分支結構的阻礙，而減緩許多。此外，因為產生分支後，PET的平衡熔點下降，以至於結晶驅動力降低，所以分支後的PET的層板結晶厚度會增加。從結晶方向性和水解測試中得知，些微分支狀的PET比起線性PET，有比較好的耐候性。

關鍵字

分支狀PET ；耐候性；結晶動力學；晶板厚度

並列摘要

Poly(ethylene terephthalate) (PET) films have found applications as the backsheets for photovoltaic devices. The properties of PET films are however gradually deteriorated upon prolonged use at ambient condition. To enhance the weathering resistance of PET, trifunctional monomers were introduced here to synthesize PET with small degree of branching. We attempt to understand the effect of such a branching on the crystallization, melting and morphology of PET films. It was found that branching in general led to a strong depression in crystallization kinetics of PET due to restriction in segmental mobility upon branching. The recrystallization of PET in the DSC heating was also hindered by branching, as manifested by the change of melting curves. Nevertheless, crystallization of the branched PET led to the formation of thicker lamellar crystals, which was attributed to the reduction of degree of supercooling due to depression of the equilibrium melting point. The introduction of slight branching did result in better resistance to hydrolysis, as demonstrated by the smaller reduction of crystal orientation and hydrolysis test in the biaxially oriented branched PET films as compared to the corresponding linear PET films.

並列關鍵字

branched PET ； weathering resistance ； crystallization kinetics ； lamellar thickness

參考文獻

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國際替代計量

分支狀PET的結晶行為以及其對耐候性的影響之研究

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