论文部分内容阅读
低取代度(DS<0.8)的NaCMC具有纤维素(Ⅱ)型的晶型结构,随DS增加结晶度迅速下降,DS>1时为无定形结构。其T_(?)随DS增加而降低,但DS=1.55的CMC的T_(?)则稍有提高。其起始分解温度(T_(?))随DS增加而增加,而分解活化能则与DS没有规律性的关系。CMC链上的平衡离子H~+、Na~+、Mg~+、Ca~+和Al~(3+)等对其结晶形态的破坏能力不同,对相同价数的离子,随离子半径增大,破坏力增强,而对半径相近的离子,高价的比低价的破坏作用明显。NaCMC的分解活化能E=251～293 kJ/mol,而高价平衡离子的CMC的E=105 kJ/mol左右。
NaCMC with low degree of substitution (DS <0.8) has a crystalline structure of cellulose (Ⅱ) type, and the degree of crystallinity decreases rapidly with DS. An amorphous structure is formed when DS> 1. The T_ (?) Decreases with increasing DS, but the T_ (?) Of CMC with DS = 1.55 increases slightly. The initial decomposition temperature (T_ (?)) Increases with increasing DS, while the decomposition activation energy has no regular relationship with DS. The ions of H +, Na +, Mg ~ +, Ca ~ + and Al ~ (3+) in the CMC chain have different ability of destroying their crystal form. For ions with the same valence, the ion radius increases , Destructive power increased, while the radius of similar ions, the destruction of high prices than the obvious role. The activation energy of decomposition of NaCMC is E = 251 ~ 293 kJ / mol, while that of high priced equilibrium ions is about 105 kJ / mol.