Natural rubber, styrene-butadiene rubber, and polybutadiene
rubber were used to replace part of the butadieneacrylonitrile
rubber in a 70/30 butadiene-acrylonitrile rubber/
poly(vinyl chloride) blend. Such replacement up to 15%
of the total weight of the blend improved the mechanical
properties, while decreasing the cost of the blend. Styrenebutadiene
rubber could replace butadiene-acrylonitrile
rubber up to 30% of the total weight of the blend without
deterioration in the mechanical properties.
Sasidharan, K K; Dr. Thomas, Kurian; Dr. Rosamma, Alex(Cochin University of Science And Technology, February , 2014)
[+]
[-]
Abstract:
Sensitisation of natural rubber latex by addition of a small quantity of
an anionic surfactant prior to the addition of a coacervant results in quick
coagulation. The natural rubber prepared by the novel coagulation method
shows improved raw rubber characteristics, better cure characteristics in
gum and carbon black filled compounds and improved mechanical
properties as compared to the conventionally coagulated natural rubber.
Compounds based on dried masterbatches prepared by the incorporation of
fluffy carbon black in different forms of soap sensitised natural rubber
latices such as fresh latex, preserved field latex, centrifuged latex and a
blend of preserved field latex and skim latex show improved cure
characteristics and vucanizate properties as compared to an equivalent
conventional dry rubber-fluffy carbon black based compound.
The latex masterbatch based vulcanizates show higher level of
crosslinking and better dispersion of filler. Vulcanizates based on fresh
natural rubber latex- dual filler masterbatches containing a blend of carbon
black and silica prepared by the modified coagulation process shows very
good mechanical and dynamic properties that could be correlated to a low
rolling resistance. The carbon black/silica/nanoclay tri-filler - fresh natural
rubber latex masterbatch based vulcanizates show improved mechanical
properties as the proportion of nanoclay increased up to 5 phr.
The fresh natural rubber latex based carbon black-silica masterbatch/
polybutadiene blend vulcanizates show superior mechanical and dynamic
properties as compared to the equivalent compound vulcanizates prepared
from the dry natural rubber-filler (conventional dry mix)/polybutadiene blends
Description:
Department of Polymer Science and Rubber Technology
Cochin University of Science and Technology
Zinc butyl xanthate [Zn(bxt)2] was prepared
in the laboratory . The effect of this xanthate with zinc
diethyl dithiocarbamate (ZDC) on the vulcanization of natural
rubber ( NR), polybutadiene rubber (BR), and NR/BR
blend has been studied at different temperatures. The
amounts of Zn (bxt)2 and ZDC in the compounds were optimized
by varying the amount of ZDC from 0 . 75 to 1.5 phr
and Zn (bxt)2 from 0 . 75 to 1 .5 phr. The cure characteristics
were also studied . HAF filled NR, BR, and NR / BR blend
compounds were cured at different temperatures from 60 to
150 C. The sheets were molded and properties such as tensile strength, tear strength, crosslink density and elongation
at break, compression set, abrasion resistance, etc. were
evaluated. The results show that the mechanical properties
of 80NR/20BR blends are closer to that of NR vulcanizates,
properties of 60NR/40BR blends are closer to BR vulcanizates,
while the 70NR/30BR blends show an intermediate
property.