Sunil,K Narayanankutty(OPA (Overseas Publishers Association), January 7, 1997)
[+]
[-]
Abstract:
Cure characteristics of short polyester fiber-polyurethane composites with respect to
different bonding agents (MD resins) based on 4, 4' diphenylmethanediisocyanate (MDI)
and various diols like propyleneglycol (PG), polypropyleneglycol (PPG) and glycerol
(GL) were studied. Tmax. - Tmin. of composites having MD resin were found to be
higher than the composite without MD resin. Minimum torque and Tmax. - Tmin.,
scorch time and optimum cure time were increased with the increase of MDI equivalence.
Optimum ratio of MDI / -of in the resin was found to be within the range of
1-1.5. It was observed from the cure characteristics that for getting better adhesion
between short polyester fiber and the polyurethane matrix the best choice of MD resin
was one based on MDI and 1:1 equivalent mixture of polypropyleneglycol and glycerol.
Sreeja, T D; Dr.Narayanankutty,Sunil K(Cochin University of Science & Technology, May , 2001)
[+]
[-]
Abstract:
The thesis deals with the development of short nylon fiber-reclaimed
rubber/elastomer composites. Three rubbers viz, natural
rubber, acrylonitrile butadiene rubber and styrene butadiene rubber
were selected and were partially replaced with reclaimed rubber.
The blend ratio was optimized with respect to cure characteristics
and mechanical properties. Reclaimed rubber replaced 40 parts of
NR and SBR and 20 parts of NBR without much affecting the
properties. These blends were then reinforced with short nylon
fibers. The mechanical properties of the composites were studied
in detail. In all the cases the tensile strength, tear strength and the
abrasion resistance increased with increase in fiber content. In the
case of NRlreclaimed rubber blends, the tensile strength-fiberloading
relationship was non-linear where as in the case of
NBRlreclaimed rubber blends and SBRlreclaimed rubber blends
the tensile strength-fiber loading relationship was linear. All the
composites showed anisotropy in mechanical properties. The effect
of bonding system on the composite properties was also studied
with respect to cure characteristics and mechanical properties. For
this, a 20 phr fiber loaded reclaimed rubber/elastomer composites
were selected and the effect of MDI/PEG resin system was studied.
The resin used was 5 phr and the resin ratios used were 0.67: I, 1:1,
1.5:1 and 2:1. The bonding system improved the tensile strength,
tear strength and abrasion resistance. The best results are with
SBRlreclaimed rubber-short nylon fiber composites. The
optimized resin ratio was 1:1 MDI/PEG for all the composites.
Description:
Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology