Development of new methodology for precision polycondensation by means of polymerization-induced oligomer crystallization

通过聚合诱导低聚物结晶开发精密缩聚新方法

• 批准号: 12450374
• 负责人: KIMURA Kunio
• 金额: $ 5.12万
• 依托单位: OKAYAMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450374/
• 关键词: Fractional polymerization; Sequence control; Unstoichiometry; Whisker; Crystallization during polymerization; Precision polycondensation; Morphology; Polyester; 精密重縮合; 剛直高分子; 連鎖配列; 等モル性

In this study, novel methodology for precision polycondensation was examined based on the new concept of the connection between solution oligomerization and solid-state polymerization by reaction-induced crystallization of oligomers.Fractional polycondensation: Polymerization of p-acetoxybenzoic acid (p-ABA) and m-acetoxybenzoic acid (m-ABA) were carried out in liquid paraffin (LPF) at 300℃ for 6 hours. Needle-like polymer crystals were obtained by the crystallization of oligomers when the molar ratio of m-ABA in feed was less than 30 mol %. The obtained crystals were comprised of poly(p-oxybenzoyl) and it was concluded that the fractional polycondensation was induced by the difference on the crystallizability between homo- and co-oligomers.Sequence control polycondensation: Copolymerizations of p-ABA and S-acetyl-4-mercaptobenzoic acid were carried out in LPF at 300℃. In the case of random copolymerization, spherical polymer products which did not possess any crystal habits were forme … More d in the middle copolymerization ratio due to the lack of crystallizability as well as tendency of liquid-liquid phase separation of oligomers. On the other hand, the copolymerization of dimers or trimers comprised from p-oxybenzoyl and p-mercaptobenzoyl units yield the whiskers at even middle copolymerization ratio. The oligomers prepared from dimers or trimers were precipitated by the crystallization due to the enhancement of sequence regularity and therefore, the copolymer whiskers were formed.Polycondensation of unstoichiometric condition: p-ABA was polymerized with p-hexyloxybenzoic acid (HOBA) or p-decyl oxybenzoic acid (DOBA) to break the balance of stoichiometry between acetoxy and carboxylic end groups. The polymer crystals prepared with HOBA of which the molar ratio in feed was 60 % exhibit very high Mn of 4.08×10^3. And those prepared with DOBA of which the molar ratio was 30 % exhibit quite high Mn of 2.78×10^4. It was concluded that Mn increased with eliminating of oligomer end groups terminated by monocarboxylic acids by trans-esterification which occurred simultaneously with crystallization.Simultaneous one-pot synthesis of poly(p-oxybenzoyl) and poly(p-aminobenzoyl) Simultaneous one-pot synthesis of poly(p-oxybenzoyl) (POB) and poly(p-aminobenzoyl) (PAB) was examined by means of the reaction induced crystallization of oligomers during solution polymerization. The copolymerizations of p-ABA and p-acetoamidobenzoic acid (AABA) were carried out in triethylbiphenyl mixture at 300℃. Needle-like and plate-like crystals were formed separately at ABA/AABA of 50 〜 30 mol%. Former crystals are mainly comprised of POB and the latter are done of PAB. The miscibility of PAB oligomer to the solvent is much lower than that of POB oligomers due to hydrogen bonding, and hereby the average DPn of phase-separated oligomer of PAB is lower, of which POB oligomer is estimated as 1.90 and PAB oligomer is done as 1.04. Kinetic study reveals that ABA can react four times faster than AABA and this difference leads to the fluctuation of composition in oligomers. Therefore, PAB oligomers tend to be precipitated earlier and PAB crystals are formed at the beginning of the polymerization. Then POB oligomers are precipitated gradually in the middle of polymerization. Less

本研究基于反应诱导结晶将溶液聚合与固相聚合联系起来的新概念，探索了精密缩聚的新方法：分步缩聚：对乙酰氧基苯甲酸（p-ABA）和间乙酰氧基苯甲酸（m-ABA）在液体石蜡（LPF）中于300℃聚合6 h。当原料中m-ABA的摩尔比小于30mol%时，通过低聚物的结晶得到针状聚合物晶体。顺序控制缩聚：对-ABA与S-乙酰基-4-巯基苯甲酸在LPF中于300℃进行共聚反应。在无规共聚的情况下，形成不具有任何结晶习性的球形聚合物产物 ...更多信息 d，这是由于低聚物缺乏结晶性以及倾向于液-液相分离。另一方面，由对氧苯甲酰基和对巯基苯甲酰基单元组成的二聚体或三聚体的共聚在甚至中等的共聚比下产生晶须。非化学计量条件下的缩聚：对-ABA与对-己氧基苯甲酸（HOBA）或对-癸氧基苯甲酸（DOBA）发生聚合，打破了端羧基与端乙酰氧基的化学计量平衡。用HOBA（其在进料中的摩尔比为60%）制备的聚合物晶体表现出非常高的Mn（4.08×10^3）。当DOBA的摩尔比为30%时，所制备的样品具有较高的Mn，为2.78×10^4。结果表明，Mn随低聚物端基的消除而增加，而端基的消除是通过与结晶同时发生的酯交换反应进行的。同时一锅法合成聚对羟基苯甲酰基和聚对氨基苯甲酰基通过溶液聚合过程中低聚物的反应诱导结晶，研究了同时一锅法合成聚对羟基苯甲酰基（POB）和聚对氨基苯甲酰基（PAB）。对乙酰氨基苯甲酸（AABA）与对乙酰氨基苯甲酸（ABA）在三乙基联苯中于300℃进行共聚反应。当阿坝/AABA为50 ~ 30mol%时，分别形成针状和片状晶体。前者主要由POB组成，后者由PAB组成。由于氢键作用，PAB低聚物对溶剂的溶解性远低于POB低聚物，因此PAB相分离低聚物的平均DPn较低，其中POB低聚物估计为1.90，PAB低聚物估计为1.04。动力学研究表明，阿坝的反应速度比AABA快4倍，这种差异导致了寡聚体组成的波动。因此，PAB低聚物倾向于较早沉淀，并且在聚合开始时形成PAB晶体。然后POB低聚物在聚合中间逐渐沉淀。少