In
this study, novel biobased pressure-sensitive adhesives (PSAs)
derived from epoxidized soybean oils and carboxylic acid-terminated
polyesters were developed with flame retardance, thermal stability,
and peel strength comparable to those of current PSAs. The dynamic
mechanical analysis indicated that the PSAs exhibited a dynamic mechanical
response consistent with related high-performance PSAs. The thermal
properties of the PSAs were investigated by thermogravimetric analysis,
and the results suggested that the onset decomposition temperatures
in both nitrogen and air atmospheres were improved by incorporating
both 9,10-dihydro-10-[2,3-di(hydroxycarbonyl)propyl]-10-phosphaphenanthrene-10-oxide
(DDP) and 2-(6-oxido-6H-dibenz<1,2>oxaphosphorin-6-yl)-1,4-hydroxyethoxyphenylene
(DOPO-HQ-HE) as the flame-retardant monomer. Microscale combustion
calorimetry, the limiting oxygen index test, UL-94, and the test method
for flame resistance of PSA tapes were used to evaluate the flame
retardance of the PSAs. With an increase in the content of the flame-retardant
monomers, the flame retardance of two phosphorus-containing PSAs improved.
The PSAs were based on renewable materials without any volatile organic
compound, thus being environmentally friendly together with having
the expected thermal stability and flame retardance. If we take advantage
of these features, the PSAs can provide more opportunities for versatile
applications.