Chen Liang,Mingxu Chen,Dongbing Jiang,Pengkun Hou,Deqiang Zhao,Shoude Wang,Ziyuan Yu,Piqi Zhao,Lingchao Lu
Developing hydrophobic agents that minimize the strength loss of bulk hydrophobic cementitious materials (BHCM) remains a formidable challenge. Substances such as siloxanes can hinder cement mineral hydration and prevent the formation of an initial network structure during the early hydration stages. In this study, a novel hydrophobic emulsion in which polydimethylsiloxane (PDMS) wrapped with modified nano silica (MNS) is designed to enhance the hydrophobic property of cementitious materials while minimizing strength loss. The results show that BHCM exhibits good hydrophobicity (water contact angle 121.8°) while significantly reducing strength loss (decreased by 10.3 %). The presence of MNS effectively shields PDMS from direct contact with cement minerals during the initial stages. Moreover, MNS can react with portlandite (CH) to generate C-S-H phase and optimize the pore structure of hardened cement pastes. This study contributes to promoting the structure-function integration of cement composites and achieving an extended service life for concrete.
Most modifications of wool focused on its surface due to the existence of the cuticle scales. For instance, chlorination, oxidation and protease treatments were used to break down or remove the scales. However, these modifications usually severely damaged the internal structure of wool. In this paper, a novel approach based on surface micro-dissolution was employed to modify the surface of wool to minimize the internal damage of wool, and improve the surface-related properties of wool. The micro-dissolution system used NaHSO 3 /urea to dissolve the scale layer of wool. After being micro-dissolved with NaHSO 3 /urea system, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), fluorescence microscopy, Fourier transform infrared spectroscopy (FTIR), and the Allwörden reaction were utilized to characterize the treated wool. Furthermore, felting shrinkage, strength loss and wettability of the treated wool were determined. The results showed that NaHSO 3 /urea system could dissolve the scale layer from outside to inside. The fluorescence microscopic images further indicated that low concentration of NaHSO 3 /urea system can dissolve the surface of wool without the serious damage of internal structure. Moreover, the micro-dissolution system can be controlled to dissolve the scale layer on the surface of wool slightly by adjusting the reaction conditions. The presented method is simple, easy to operate, and economical, thereby can open up new directions for the surface modification of wool.
危险品化学品经营许可证（带存储）