Development of a dedicated primer for ballastless track organic silicon sealant
DAI Feiliang
FU Zien
LUO Yuanzhang
WU Feng
YAN Zimin
Abstract：A two-step prepolymer method was used to chemically graft polydimethylsiloxane(PDMS)segments onto the main chain of polyurethane(PU)to prepare a structurally uniform block copolymer(PU-b-PDMS),which was applied as a primer for sili-cone sealant in ballastless track.The results demonstrate that the optimal comprehensive performance is achieved when m(PDMS)/m(PU)=0.3,MDIis selected as the hard segment,PPG-2000 serves as the soft segment,and n(—NCO):n(—OH)=1.8.Under these conditions,the copolymer exhibits a bond strength of 4.64 MPa with concrete,achieves 100%cohesive failure with silicone sealant,and possesses suitable curing speed and storage stability.FT-IR analysis confirms the successful synthesis of the target product,combining the strong adhesion of polyurethane and excellent compatibility of silicone.
Keywords：polyurethanepolydimethylsiloxaneblock copolymerorganic silicone sealantprimerballastless track
Publication Date：2025-12-25
Online Publishing Date：2026-01-13(First online date of this platform, not the publication date of the document)
Pages：4( 103-106 )