Analysis of the Amorphous and Interphase Influence of Comononomer Loading on Polymer Properties toward Forwarding Bioadvantaged Copolyamides
Analysis of the Amorphous and Interphase Influence of Comononomer Loading on Polymer Properties toward Forwarding Bioadvantaged Copolyamides
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DOI：
10.1021/acs.macromol.1c00651
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发表时间：
2021-08-17
期刊：
影响因子：
5.5
通讯作者：
Cochran, Eric W.
中科院分区：
文献类型：
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作者：
Abdolmohammadi, Sanaz;Gansebom, Dustin;Cochran, Eric W.
在这里，我们提出了一种通过引入“生物优势”基团来选择性地修饰半结晶聚合物性质的方法。通过这种方法，可以利用生物质的独特功能来定制半晶聚合物的非晶相的特性，而对结晶度和热机械性能的影响最小。以具有生物优势的单体反式3-己烯二酸（t3HDA）为原料，制备了pa6,6共聚物。t3HDA与己二酸（pa6,6单体）的类似结构允许无缝集成。在整个组成范围内进行筛选，确定了t3HDA负载（20 mol %），超过该负载，性能明显偏离尼龙6,6。一旦确定，合适的组成的共聚物将升级到商业质量，并充分表征，以评估负载和聚合物结构对热性能和机械性能的影响。采用凝胶渗透色谱（GPC）、质子核磁共振谱（H-1 NMR）、异核单量子相干谱（HSQC）、广角x射线散射（WAXS）、差示扫描量热（DSC）、热重分析（TGA）、动态力学分析（DMA）、拉伸测试、弯曲测试和吸水测试等方法对样品进行表征。结果表明，在3-羟基己二酸（3HHDA）的剧烈缩聚过程中，t3HDA单元水合物化，并完全融入聚合物骨架中。加载水平高达20%时，在干燥状态下具有相当的热性能和机械性能，但吸湿性（一种已知的提高聚酰胺韧性、屈服应变和伸长率的方法）在20%加载时提高了100%以上。对生物优势共聚物的案例研究阐明了可以用于推进增值可再生聚合物的控制结构-功能原理。
Here we present an approach for selectively modifying the properties of semicrystalline polymers by introducing "bioadvantaged" counits. With this approach, the unique functionality of biomass can be leveraged to tailor the properties of the amorphous phase of semicrystalline polymers with minimal impact on crystallinity and thermomechanical properties. As a model case, PA 6,6 copolyamides were produced using the bioadvantaged monomer trans-3-hexenedioic acid (t3HDA). The analogous structure of t3HDA to adipic acid, a PA 6,6 monomer, allows for a seamless integration. Screening over the entire composition range identified the t3HDA loading (20 mol %) beyond which properties deviate appreciably from Nylon 6,6. Once identified, copolyamides of suitable compositions were upgraded to commercial quality and fully characterized to assess the influence of counit loading and polymer structure on thermal and mechanical properties. Samples were characterized using gel permeation chromatography (GPC), proton nuclear magnetic resonance spectroscopy (H-1 NMR), heteronuclear single quantum coherence spectroscopy (HSQC), wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), tensile testing, flexural testing, and water absorption testing. t3HDA units were shown to hydrate during the harsh polycondensation to 3-hydroxyhexanedioic acid (3HHDA) and fully incorporate into the polymer backbone. Loading levels up to 20% were shown to have comparable thermal and mechanical properties in the dry state, yet moisture absorption-a known method for improving the toughness, yield strain, and elongation of polyamides-was enhanced by over 100% at 20% loading. This case study on bioadvantaged copolymers elucidates the governing structure-function principles that can be leveraged to forward value-added renewable polymers.