材料科学
触变性
复合材料
流变学
小角X射线散射
扫描电子显微镜
聚酯纤维
化学工程
散射
高分子科学
光学
物理
工程类
作者
Yingfeng He,Ssu-Ting Huang,Chia‐Hao Chen,Yu‐Hsuan Chang,Chi‐Chung Hua,Ping-Ray Chiang,Jien-Yi Weng
出处
期刊:Soft Matter
[The Royal Society of Chemistry]
日期:2021-01-01
卷期号:17 (47): 10628-10639
被引量:1
摘要
Four representative bisurea molecules (HDI-BA, MDI-BA, TDI-BA, and IPDI-BA) were synthesized and dispersed simultaneously by reacting benzylamine (BA) with various types of diisocyanates in a polyester/ortho-xylene resin medium to produce bisurea-loaded resins (BLRs) for anti-sagging application with paints and coating materials. These bisurea molecules are symmetric and differ only in the central spacer unit, thereby presenting an ideal and simplest model system to delve into the structure-performance relationship. The multiscale structural features arising from self-assembly in each of the BLRs were scrutinized using the combination of multi-angular dynamic light scattering (DLS), small-angle light/X-ray scattering (SALS/SAXS), rheology, and scanning electron/optical microscopy (SEM/OM) characterization. All four BLRs were revealed to foster micron-sized, mostly sphere-like agglomerates, with distinct hierarchical structures that correlate well with their thixotropic and anti-sagging performances. Three BLRs (HDI-BA, MDI-BA, and TDI-BA) produce similar rod-like packing units (10 × 1 × 1 nm3), with only one exception (IPDI-BA) that produces a spherical packing unit (2 nm in diameter). However, the bulk feature of the agglomeration state, which dictates the thixotropic and anti-sagging properties, cannot be readily foreseen from the chemical structure or elementary packing unit of a bisurea. The present findings, while confirming the importance of optimum molecular design that controls the early-stage self-assembly behavior of a bisurea in resin media, highlight the necessity of resolving detailed (multiscale) structural features in order to establish the full structure-performance relationship imperatively needed for like material systems and applications.
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