Methyl methacrylate has been grafted onto cellulose pulp using manganic ion as the initiator. The variable parameters studied are initiator and monomer concentrations, temperature and reaction time. The grafting efficiency, degree of grafting and frequency of grafting are found to be dependent on the above mentioned variables.
ZUSAMMENFASSUNG:Mit Mangan-Ionen als Initiator wurde Methylmethacrylat a d Cellulose gepfropft. Als verinderliche Parameter wurden die Initiator-und Monomerkonzentration, die Temperatur und die Reaktionszeit untersucht. Es wurde gefunden, da13 der Wirkungsgrad der Pfropfreaktion, der Pfropfungsgrad und die Haufigkeit von den genannten Parametern abhangen.
For study of maleate/fumarate isomerisation in unsaturated polyesters infrared technique was used without using model compounds. This was done by solving the following equation for two different polyesters or one polyester with two concentrations for the molar extinction coefficients at 675 crn-1 for maleate and 980 cm-1 for fumarate.Percentages of maleate and fumarate are given by following equations :The out of plane vibration of CH for maleate appeared a t slightly lower frequency, i.e. at 675 cm-1 due to steric hindrance. It was noted that the increase of the ratio of maleate to saturated acid in the polyester enhances the conversion from maleate to fumarate due to coiling tendency of the chain and causing steric compression. This tendency was also shown by phthalic anhydride based polyesters due to ortho carboxylic group compared with adipic acid and isophthalic acid. It is evident from more conversion from maleate to fumarate in case of phthalic anhydride based polyesters than that of isophthalic acid and adipic acid based polyesters. I n case of bisphenol-A based polyesters, low conversion from maleate to fumarate took place, because of less coiling of between the two segments of the chain which are phenyl groups associated through carboxyl group of maleate. Conversion was more pronounced in polyesters based on 2.2-di-(4-hydroxy-3.5-dibromophenyl) propane and 2.2-di-(4-*) At present a
Chlorinated poly(vinyl chloride) (CPVC) is known to have a higher softening temperature than conventional poly(vinyl chloride) (PVC). Its processability characteristics are, however, different; it has been reported that CPVC is more difficult to process. However, only limited information on the processability characteristics is available. This paper describes some studies of the flow behavior of CPVC melts in a capillary rheometer. The true melt viscosity and activation energy were determined between 190° and 210°C for a number of samples, and they appear to be related to the cohesive energy density of the samples. It was observed that melt fracture, i.e., gross distortion of the extrudate, occurs even at low shear rates in samples having a high chlorine content. This has been attributed to the relatively high pressures that have to be used, the pronounced non‐Newtonian nature of the melt, and melt elasticity. It is postulated that melt elasticity could result from crosslinking at the site of the double bond which is known to be formed by dehydrochlorination.
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