Regiospecific Poly(ethylene-co-vinyl alcohol) by ROMP of 3-Acetoxycyclooctene and Postpolymerization Modification for Barrier Material Applications
Regiospecific Poly(ethylene-co-vinyl alcohol) by ROMP of 3-Acetoxycyclooctene and Postpolymerization Modification for Barrier Material Applications
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通过 3-乙酰氧基环辛烯的 ROMP 和后聚合改性制备区域特异性聚（乙烯-乙烯醇），用于阻隔材料应用
DOI：
10.1021/acsapm.2c01918
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发表时间：
2023
影响因子：
5
通讯作者：
Hillmyer, Marc A.
中科院分区：
文献类型：
--
作者：
Dingwell, Claire E.;Hillmyer, Marc A.
乙烯-乙烯醇（EVOH）是一种氧气阻隔聚合物，由于其半结晶性、强的分子间相互作用和因此的低自由体积，用于防止食品、药品和其他产品的过早降解。EVOH是使用传统的自由基共聚制备的，这导致结构规则性很小。我们利用开环易位聚合（ROMP）来确定区域规整性如何影响EVOH相关材料的阻隔性能。由3-乙酰氧基环辛烯的ROMP合成区域规则（头-尾）聚合物，然后通过氢化和脱酰化得到含有75摩尔%当量的乙烯单元的线性、高度区域规则的EVOH（PH 3OHCOE）。用5-乙酰氧基环辛烯进行相同的过程，但所得聚合物（PH 5 OHCOE）是区域无规的。将两种聚合物与工业基准EVOH-44（含有44摩尔%乙烯单元）进行比较。加工后，差示扫描量热法显示，与半结晶PH 5 OHCOE相比，半结晶PH 3OHCOE具有更高的熔融温度和熔融焓，表明PH 3OHCOE更结晶。这是通过广角X射线散射（WAXS）证实的。WAXS、流变学研究和偏光显微镜显示，与PH 5 OHCOE相比，PH 3OHCOE具有更明确的晶体结构、−OH基团之间更高程度的氢键和更高的玻璃化转变温度。这些差异也在它们的拉伸行为中突出显示，其中PH 3OHCOE和EVOH-44与对于PH 5 OHCOE观察到的延性行为相比表现出脆性失效。氧阻隔测试表明，区域规则的PH 3OHCOE具有比区域无规的PH 5 OHCOE低3倍以上的氧渗透率，但仍高于EVOH-44，而水阻隔测试表明，PH 3OHCOE具有最低的水渗透率，比EVOH-44低6倍以上。这些结果强调了区域规则性对EVOH类材料阻隔性能的重要性，并表明结构规则性可以降低透氧性，同时在低乙烯醇含量下保持低透水性。
Ethylene vinyl alcohol (EVOH) is an oxygen barrier polymer used to prevent premature degradation of food, pharmaceuticals, and other products due to its semicrystallinity, strong intermolecular interactions, and consequently low free volume. EVOH is made using traditional free-radical copolymerization, which leads to little structural regularity. We utilized ring-opening metathesis polymerization (ROMP) to determine how regioregularity impacts the barrier properties of EVOH-related materials. A regioregular (head-to-tail) polymer was synthesized from ROMP of 3-acetoxycyclooctene, followed by hydrogenation and deacylation to give a linear, highly regioregular EVOH (PH3OHCOE) containing the equivalent of 75 mol % ethylene units. The same process was carried out with 5-acetoxycyclooctene, but the resulting polymer (PH5OHCOE) is regiorandom. Both polymers were compared to an industry benchmark, EVOH-44, containing 44 mol % ethylene units. After processing, differential scanning calorimetry showed that the semicrystalline PH3OHCOE had a higher melting temperature and enthalpy of melting compared to semicrystalline PH5OHCOE, indicating that PH3OHCOE is more crystalline. This was confirmed by wide-angle X-ray scattering (WAXS). WAXS, rheological studies, and polarized optical microscopy showed that PH3OHCOE has a more well-defined crystal structure, a higher degree of hydrogen-bonding between −OH groups, and a higher glass transition temperature compared to PH5OHCOE. These differences were also highlighted in their tensile behavior, where PH3OHCOE and EVOH-44 exhibited brittle failure compared to the ductile behavior observed for PH5OHCOE. Oxygen barrier testing demonstrated that regioregular PH3OHCOE had an oxygen permeability more than a factor of 3 lower than regiorandom PH5OHCOE but still higher than EVOH-44, while water barrier testing showed that PH3OHCOE had the lowest water permeability, more than 6 times lower than EVOH-44. These results highlight the importance of regioregularity on the barrier properties of EVOH-like materials and show that structural regularity can lower oxygen permeability while maintaining low water permeability at the low vinyl alcohol content.
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乙烯乙烯醇树脂作为多层包装中的阻隔材料
影响因子：
3.1
作者：
A. L. Blackwell
通讯作者：
A. L. Blackwell
通过质子和碳 13 NMR 研究乙烯-乙烯醇共聚物的立构规整性、序列分布、异常键和烷基链支化
影响因子：
5.5
作者：
H. Ketels;J. Beulen;G. V. D. Velden
通讯作者：
G. V. D. Velden
影响因子：
--
作者：
MANDELKERN, L;ALLOU, AL;GOPALAN, M
通讯作者：
GOPALAN, M
乙烯-乙烯醇共聚物的结晶度
影响因子：
--
作者：
Tsunetaka Matsumoto;K. Nakamae;Nobuaki Ogoshi;Masashi Kawasoe;Hideaki Oka
通讯作者：
Hideaki Oka
羟基功能化环戊烯钌催化平衡开环复分解聚合一锅法合成聚乙烯醇（PVA）共聚物
DOI：
--
发表时间：
2014
期刊：
影响因子：
--
作者：
Róbert Tuba;M. Al‐Hashimi;Hassan S. Bazzi;R. Grubbs
通讯作者：
R. Grubbs