Rani, Joseph(Optical Society of America, October 29, 2001)
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Abstract:
A new polymer matrix sensitized with methylene blue for use as an optical recording material is described
here. The characterization is done to determine the optimal recording conditions. These films need no
chemical development and are found to be stable for several months. The matrix has excellent shelf life
and needs an exposure only as short as 20 s. Direct imaging was done on this material.
New oligomer-bound antioxidants have been prepared by condensation reaction. The efficiency and permanence of these oligomer-
bound paraphenylene diamines as antioxidants has been compared with conventional amine type antioxidants in NR, SBR,
IIR and NBR and in elastomer blends like NR/BR and NR/SBR. The oligomer-bound antioxidants are found to impart improved
ozone, flex resistance and mechanical properties to the vulcanizates of NR, SBR, IIR and NBR and to blends of NR/BR and NR/
SBR in comparison with those containing conventional antioxidants.
Carboxy Terminated Liquid Natural Rubber (CTNR) was
prepared by photochemical reaction using maleic anhydride and masticated
natural rubber (NR). The use of CTNR as an adhesive in bonding rubber to
rubber and rubber to metal was studied. The peel strengths and lap shear
strengths of the adherends which were bonded using CTNR were determined.
The effect of using a tri isocyanate with CTNR in rubber to metal bonding was
also studied. It is found that CTNR can effectively be used in bonding rubber to
rubber and rubber to mild steel.
ABSTRACT: Phenol was chemically attached to low molecular weight
chlorinated polyisobutylene and stearic acid respectively. These phenolic
antioxidants were characterised by IR, 1H NMR and TGA. The efficiency and
permanence of these bound antioxidants were compared with conventional
antioxidants in natural rubber vulcanisates. The vulcanisates showed comparable
ageing resistance in comparison to vulcanisates containing conventional
antioxidants. The presence of liquid polymer bound phenol reduce the amount of
plasticiser required for compounding.
Rani, Joseph(Indian Academy of Sciences, February 24, 2003)
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Abstract:
Significant results of our experimental investigations on the dependence of pH on real time
transmission characteristics on recording media fabricated by doping PVC with complexed methylene blue
are presented. The optimum pH value for faster bleaching was found to be 4 . 5. In typical applications, the
illumination from one side, normal to the surface of this material, initiates a chemical sequence that records
the incident light pattern in the polymer. Thus direct imaging can be successfully done on this sample. The
recorded letters were very legible with good contrast and no scattering centres. Diffraction efficiency
measurements were also carried out on this material.