Structuring of hydroxy-terminated polydimethylsiloxane filled by fumed silica

Bibliographic Details
Title: Structuring of hydroxy-terminated polydimethylsiloxane filled by fumed silica
Authors: Peng Zhengwei, Qin Yan, Song Jiuqiang, Zhu Di, Chen Shuisheng, Ren Jingwen, Li ZhuangZhuang, Zou Zhenyue
Source: e-Polymers, Vol 21, Iss 1, Pp 131-139 (2021)
Publisher Information: De Gruyter, 2021.
Publication Year: 2021
Subject Terms: pdms, rtv, crepe hardening, structuring, fumed silica, Polymers and polymer manufacture, TP1080-1185
More Details: The term “structuring” used in silicone rubber describes a phenomenon of the increase in the viscosity of polydimethylsiloxane filled with silica during storage, which limits the applications of the room temperature vulcanized (RTV) silicone rubber in the field of aerospace and military. In this pursuit, the present study was envisaged to solve the problem of structuring of the RTV. A solvent-free method was used to hydrophobize the hydrophilic silica with hexamethyldisilazane. An RTV composition prepared using eight parts of hydrophobic silica with 2.91% C content exhibited a viscosity of less than 100 Pa s, with no significant change in 21 days. In contrast, eight parts of the hydrophilic fumed silica showed an initial viscosity of RTV to be greater than 2,000 Pa s. Silica samples with different adsorbed water content were used to prepare the RTV compositions. It was found that the viscosity of the RTV prepared using the sufficiently dried silica was 5.6 times lower than that of the wet silica. The “dissolution” model of the silica–silica hydrogen bonds in water was proposed. Furthermore, the change in the viscosity of the RTV compositions at different temperatures in the range of −15°C to 30°C was studied. The viscosity of RTV stored at –15°C for 34 days did not change significantly, whereas that stored at room temperature increased from 100 to 1,710 Pa s within 21 days.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1618-7229
Relation: https://doaj.org/toc/1618-7229
DOI: 10.1515/epoly-2021-0012
Access URL: https://doaj.org/article/73b7d618556b41bb9f931380737bd680
Accession Number: edsdoj.73b7d618556b41bb9f931380737bd680
Database: Directory of Open Access Journals
More Details
ISSN:16187229
DOI:10.1515/epoly-2021-0012
Published in:e-Polymers
Language:English