丁苯乳胶粉在早期水泥砂浆中形成聚合物膜结构的形态

丁苯乳胶粉在早期水泥砂浆中形成聚合物膜结构的形态

彭  宇¹，赵国荣²，王培铭²，孔亚宁³，赵丕琪⁴

(1.浙江大学建筑工程学院，浙江 杭州310058；2. 同济大学材料科学与工程学院，上海201804；3. 中建西部建设建材科学研究院，四川成都610000；4.济南大学绿色建材制备与测试重点实验室，山东 济南250022)

摘要  通过场发射环境扫描电子显微镜研究了丁苯乳胶粉在早期水泥净浆及砂浆中形成聚合物膜结构的形态，并结合X射线计算机断层扫描技术探究了丁苯乳胶粉改性水泥砂浆中的孔结构参数。结果表明：丁苯乳胶粉在新拌及硬化水泥净浆和砂浆中形成聚合物膜结构的形态较为多样，可桥接或覆盖在临近水化产物或集料表面，在局部区域形成复合共生区。丁苯乳胶粉的加入增大了水泥砂浆的孔隙率、平均孔径和中值孔径，降低了平均球度数值，改变了水泥砂浆孔的三维形状。

关键词  丁二烯-苯乙烯橡胶；可再分散乳胶粉；聚合物膜；复合共生区；形态

中图分类号：TU528；TU578.1　　文献标识码：A     doi:10.3969/j.issn.1000-6281.2019.04.007

Morphology of polymer film in cement mortars modified by SBR redispersible polymer powders at early ages

PENG Yu¹，ZHAO Guo-rong²，WANG Pei-ming²，KONG Ya-ning³，ZHAO Pi-qi⁴

(1. College of Civil Engineering and Architecture, Zhejiang University, Hangzhou Zhejiang310058；2.School of Materials Science and Engineering, Tongji University, Shanghai 201804；3. Building Materials Science Academy of China West Construction Group Co., Ltd, Chengdu Sichuan610000；4.Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Jinan Shandong250022, China)

Abstract  Morphology of polymer film in fresh cement pastes modified by SBR redispersible polymer powders at early ages were studied by field emission environmental scanning electron microscopy(FE-ESEM), characteristics of pore structure in hardened cement mortars modified by SBR redispersible polymer powders were also studied by ESEM accompanied with X-ray Computed Tomography (X-CT).Results show that the morphology of SBR polymer film in both fresh cement pastes and hardened cement mortars were various, bridging or covering between cement hydrates and aggregates randomly, making local region becoming into hybrid intergrowth zones(HIZ). Porosity, Average pore diameter and Mean pore diameter of blank cement mortars had all been increased by SBR redispersible polymer powers. But Mean sphericity had been decreased by the polymers, which had implied that 3D shapes of pores in cement mortars had been changed.

Keywords  styrene-butadiene rubber; redispersible polymer powders; polymer film; hybrid intergrowth zone; morphology

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