在低於玻璃化轉變溫度的聚乳酸中觀察到強度與結晶度之間的負相關關係。 研究顯示，無定形區域中的分子交纏在一起達到了承重結構的作用，並引起應力誘發的裂紋。用三相模型來解釋非晶區隨熱處理在玻璃轉移溫度下的聚合物模數的變化。將碳量子點與非晶態的聚乳酸結合產生新型的發光復合材料，這種複合材料可用於食品標籤，追踪，包裝和原產地生產。

A negative relation between strength and crystallinity is observed in polylactic acid (PLA) below glass transition temperature. Study indicates that entangled molecules in amorphous regions act as load bearing structures and are responsible for stress induced crazing. A three-phase model is proposed to explain how amorphous fraction changes with heat treatments and contributes to polymer modulus below glass transition temperature. Incorporation of carbon quantum dots into amorphous fraction dominated PLA creates a new type of luminescent composites that can be used for food labelling, tracking, packaging and production of origin.

Abstrate I
摘要 II
致謝 III
Chapter 1 1
Introduction 1
1-1 Research Background and motivation 3
1-2 The structure and properties of PLA 3
1-3 Synthesis of PLA 8
1-4 Applications and advantage 9
1-5 The properties of carbon quantum dots 10
Chapter 2 11
Experimental Section 11
2-1 Instrument introduction 11
2-2 Sample preparations 22
2-3 Instrument settings 23
Chapter 3 24
Results and discussion 24
3-1 Optical microscope analysis 24
3-2 XRD analysis 26
3-3 DSC analysis 28
3-4 Three-point bending measurements 29
3-5 DMA analysis 31
3-6 FTIR analysis 33
3-7 Polymer crazing 34
3-8 PLA applications 37
Chapter 4 40
Conclusions 40
References 41

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