Synthesis and characterisation of castor oil-urethane acrylate oligomers

Authors
Citation
Z. Wang et P. Gao, Synthesis and characterisation of castor oil-urethane acrylate oligomers, SURF COAT I, 84(1), 2001, pp. 21-26
Citations number
8
Categorie Soggetti
Chemical Engineering
Journal title
SURFACE COATINGS INTERNATIONAL PART B-COATINGS TRANSACTIONS
ISSN journal
13560751 → ACNP
Volume
84
Issue
1
Year of publication
2001
Pages
21 - 26
Database
ISI
SICI code
1356-0751(200101)84:1<21:SACOCO>2.0.ZU;2-2
Abstract
Castor oil-urethane acrylate (CVA) oligomers have been synthesised and char acterised by intra-red spectroscopy (FT-IR), gel permeation chromatography( GPC) to study the relationship between the reaction kinetics and the struct ure of the products. It is shown that the chain terminating reaction betwee n 2,4-toluene diisocyanate (2,4TDI) and hydroxyethylacrylate (HEA) to form isocyanatoethyl acrylate (IEA) obeys a second order mechanism, as does the chain extension reaction of IEA and castor oil (CAS). From the data of the polymerisation rate constant and the apparent activation energy, it can be seen that the different structure of CVA oligomer is dependent mainly on th e different reactivities of both para and ortho NCO groups in 2,4TDI. Where as the apparent viscosity of the CVA oligomer is related to the structure o f diisocyanates. Results from the dynamic mechanical spectrum (DMS, the abs tract of dynamic mechanical spectrum, a kind of detection method) indicate that the hard segment content of oligomers is then increased up to 59% (wt. ). A phase-separated structure is formed and leads to the highest tensile s trength (18.2MPa). When the hard segment content is increased to 67% (wt.), the dynamic modulus is reduced and the single depletion peak from DMS is e xhibited at the temperature of 100.7 degrees.