Natural rubber, Chemistry

Natural rubber: Natural rubber is obtained by making small incisions on the bark of certain types of trees, like "Have a brasiliensis" and "Ganynle". White milky liquid substance (rubber latex) from the rubber tree by tapping is obtained. Latex is sieved to remove impurities then coagulated using coagulants like acetic acid or formic acid. Coagulated mass convert into coagulum. Coagulum is washed, dried and treated as follows:

1. Copper rubber: It is prepared by adding, little amount of sodium bisulphite, a retarder prevents, the discoloration and softening of rubber. Coagulum is allowed to drain for about two hours and after that it is passed through a creeping machine to form sheets of rubber of about 1 mm.

2. Smoked sheet: For preparing smoked sheets coagulation is carried out in long tanks. Sides of the tank have vertical grooves fitted with metal plates. First, dilute latex is added into the tanks and before that plates are removed. Coagulating agent, formic acid or acetic acid is then added and mixture is thoroughly stirred then plates are fitted and allowed to dry slabs are formed.

 

 

Posted Date: 7/21/2012 8:21:01 AM | Location : United States







Related Discussions:- Natural rubber, Assignment Help, Ask Question on Natural rubber, Get Answer, Expert's Help, Natural rubber Discussions

Write discussion on Natural rubber
Your posts are moderated
Related Questions
CACO3   CAO+CO2 IF CAO IS ADDED EXTERNALLY WHAT WILL BE THE CHANGE{WILL FWD REACTION INC OR BACKWARD REACTION INC}AND WHY ? Solution) Backward reaction, due to Le Chatelier''s

0.45 g of anhydrous oxalic acid is reacted with 50 ml of KMNO4 . Then normality of KMnO4 is??

The energy of second Bohr orbit of the hydrogen atom is -328 kJ mol-1, hence the energy of fourth Bohr orbit would be: (1) - 41 kJ mol -1 (2) -1312 kJ mol -1   (3) -164

I get stuck on how to explain things.. eg I need to explain that you coat 5 nails and put one different nail with a different coating into a different substance etc, and i just can

The number of electrons in [ 40 19 k ] -1   is: (1) 19      (2) 20      (3)18     (4)40 Ans: 40

Define Enable the Acquisition of Powers of Observation I.  PURPOSE OF THE EXPERIMENT The purpose of the experiment is to enable the acquisition of powers of observatio

Q. Objective of elements of group 16? You should be able to: • describe the occurrence, extraction and uses of the elements of Group 16, • describe the allotropic forms o


Question: (i) List the different members of the marine mammalian groups. (ii) Explain the term "stranding" and give some reasons why cetaceans strand? (iii) Cetacean

In the anaerobic fermentation of grain the yeast Saccharomyces cerevisiae digests glucose from plants to form the products ethanol and propenoic acid by the following overall react