高分子氫鍵作用力與交聯動力學之研究

Abstract

研究兩相Polybenzoxazine（PBZZ）/ Poly (N-vinyl-2-pyrrolidone)（PVP）摻合的熱穩定性與氫鍵作用力行為，最常用微差掃描熱分析儀（DSC）與傅立葉轉換紅外線光譜儀（FT-IR）。DSC結果得知一個玻璃轉移溫度（Tg），表示此兩相系統均勻混摻，且Tg為正偏差符合Kwei equation。由傅立葉轉換紅外線光譜得知兩相摻合有氫鍵作用力存在，本篇論文第一部分主要研究此兩相摻合的氫鍵是屬於分子間或分子內自身作用力，研究結果得知氫鍵作用力平衡常數大小依序為：PBZZ的羥基與PVP的羰基互相作用力平衡常數KA（594 Lmol-1）＞PBZZ的羥基自身作用平衡常數KB（72.6 Lmol-1）＞分子內PBZZ的羥基與胺基自身作用平衡常數KC（＜10 Lmol-1）。 Benzoxazines利用開環產生聚合反應，而聚合後之poly benzoxazines（PBZZ）改善了傳統phenolic resin的脆性與縮合反應時會產生H2O、NH3等小分子之缺點、無如同phenolic resin中殘留phenol有毒物之可能性、且無需催化劑之使用，並提供較寬的加工條件。 本實驗第二部分主要目的：要求出P-a type 和B-a type co-poly benzoxazines進行熱交聯聚合的動力學參數(如：活化能、轉化率、反應熱與模式)。實驗乃是將兩種benzoxazine用乙醚溶解並均勻混合，於溶劑抽掉後分別在160、180、190、200、210、220℃恆溫4小時測玻璃轉移溫度，觀測交聯溫度與玻璃轉移溫度之關係。此外利用DSC作動態與恆溫的交聯反應，利用三種動力學分析模式Kissinger、Osawa、Kamal等方法，分別算出活化能為72.11、84.06、50.32KJ/mol，反應的級數介於2.66至3.03之間，阿瑞尼雅斯常數為7963。

The thermal properties and hydrogen bonding behavior of polybenzoxazine (B-a type)/poly (N-vinyl-2-pyrrolidone) (PVP) blends were investigated by using differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The DSC result shows a single glass transition temperature (Tg) over the entire compositions, indicating that the amorphous phase of polybenzoxazine (PBZZ) is totally miscible with PVP. In addition, a large positive deviation based on Kwei equation was observed in the Tg versus composition diagram, implying that strong hydrogen bonding interaction exists between the hydroxyl group of PBZZ and the carbonyl group of PVP. The FTIR analysis also provides positive evidence for the hydrogen bonding interaction existing between these two polymers. The equilibrium constants, including self- and inter-association hydrogen bonding, were determined from appropriate low molar mass mixtures, which can be used to predict the miscibility behavior and hydrogen bonding interaction of analogous polymers. The strength of hydrogen bonding interaction is found in the order of: inter-association between PBZZ hydroxyl and PVP carbonyl ＞ self-association between PVP hydroxyl ＞ inter-association between PBZZ hydroxyl and the Mannich-based bridge. The structure of benzoxazines is similar to phenolic resin through thermal self-curing of the heterocyclic ring opening reaction that neither requires catalyst nor releases any condensation byproduct, and these polybenzoxazine resins own several outstanding properties. For the reason, in order to get a better understanding of the curing kinetics of the copolybenzoxazine thermosetting resin, the differential scanning calorimetric (DSC) measurement was performed during dynamic and isothermal experiments. To go a step further, three kind kinetic analysis models; Kissinger method, Flynn-Wall-Osawa method and Kamal method; were used to describe the curing process, respectively. Finally, the results of activation energies that calculated by Kissinger method and Flynn-Wall-Osawa method that used for dynamic kinetic analysis are 72.11 and 84.06 KJ/mol, respectively. Furthermore, Kamal method that used for an autocatalytic model in this system with a total order of reaction is between 2.66 and 3.03 depends on the isothermal curing temperatures. Besides, its activation energy and Arrhenius preexponential are 50.32 KJ/mol and 7963.