- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fluorescence Study of the Hydrolytic Degradation Process of the Polysiloxane Coatings of Basalt Fibers
摘要： Basalt fiber surfaces were modified using different silane aqueous solutions to generate a variety of polyorganosiloxane coatings. After removing the commercial coating of the fibers by calcination and subsequent activation processes, polysiloxanes were grafted on the fiber surfaces. Three aqueous solutions were used for the silanization: i) γ-aminopropyltriethoxysilane, APTES; ii) γ-aminopropylmethyldiethoxysilane, APDES, and iii) a mixture of 50% by weight of both APTES+APDES. The silanized fibers were chemically labeled with fluorescein isothiocyanate to be immersed afterwards in different aqueous solutions (pH=7) to study the hydrolytic degradation of the polysiloxane coatings. The hydrolysis phenomena were monitored by steady state fluorescence at different temperatures to subsequently study the kinetics of the process. The hydrolysis process was also studied by monitoring the pH of the solution in which the silanized fibers were immersed as a function of time. The data obtained from fluorimetry were fitted to an integrated expression arising from a first order kinetic process, which allowed estimation of the activation energies of the hydrolytic degradations. The results indicated that although the hydrolytic rate of the polysiloxane coatings increased in the order APDES<APDES+APTES<APTES, differences in the mechanism were not the cause of that order; the initial concentration of siloxane bonds able to be hydrolyzed was responsible.
关键词： polyorganosiloxane,hydrolytic degradation,fluorescence,Basalt fibers
更新于2025-09-23 15:22:29
-
Improved output voltage of 0–3 cementitious piezoelectric composites with basalt fibers
摘要： In this paper, basalt fibers (BF) was employed as high modulus component with good interface bonding with cement matrix to enhance local stress applied on piezoelectric ceramic particles in 0–3 cementitious piezoelectric composites (0–3 CPCs). The effect of content of BF varying from 0.00 vol% to 0.23 vol% on the mechanical, piezoelectric and dielectric properties of 0–3 CPCs and the output voltage of 0–3 CPCs sensor was evaluated. The results showed that amplitude of output voltage of the 0–3 CPCs sensor with 0.12 vol% BF maximized at 4.98 V, which was 60.0% higher than that of the 0–3 CPCs sensor without fibers for the compact structure of the 0–3 CPCs and good interface bonding between BF and cement matrix as a reason of good stress transfer in the composites. While the split tensile strength, piezoelectric voltage constant (g33), piezoelectric strain constant (d33), relative dielectric constant (εr) and dissipation factor (tanδ) was 13.1 MPa, 11.36 × 10?3 V m/N, 43 pC/N, 430.0 and 0.43, respectively. It provided a novel method to improve the mechanical-electrical response of piezoelectric sensor by enhancing local stress applied on piezoelectric ceramic particles in the piezoelectric composites.
关键词： 0–3 cementitious piezoelectric composites,Stress transfer,Basalt fibers,Output voltage
更新于2025-09-23 15:19:57