What is mastication process of rubber?
Mastication, the process by which the viscosity of natural rubber is reduced to a suitable level, is an important step in the mixing process. Rubber polymers such as Natural Rubber (NR) require mastication to reduce their viscosity/elasticity and to even out variations between different polymer lots.
What are the factors affect on rubber mastication?
The mastication of natural rubber results in the shortening of the long molecular chains, which affects the viscosity of the material. Mechanical and thermo-oxidative breakdowns are the two major factors that interfere during mastication and processing of natural rubber.
Why do synthetic rubbers not need mastication?
Most synthetic rubbers do not need the mastication step because they are made of shorter molecules. Mixing and blending are still required, however, to combine all ingredients used in the rubber compound. To begin the process bales of rubber first may be cut into pieces.
What are the methods of processing rubber?
Rubber processing consists of four basic steps: (1) mastication, when the elastomer is sheared and the molecules are broken down to give easier flow, (2) mixing, usually carried out immediately after mastication, when additives are incorporated, (3) shaping of the viscous mass, for example, by extrusion or molding, and …
What is curing of rubber?
Curing, also known as vulcanization, causes the long polymer chains that rubber is composed of to become crosslinked. This prevents the chains from moving independently, allowing the material to stretch under stress and then return to its original shape when the stress is released.
What is Mooney viscosity in rubber?
Mooney viscosity is defined as the shearing torque resisting rotation of a cylindrical metal disk (or rotor) embedded in rubber within a cylindrical cavity. The dimensions of the shearing disk viscometer, test temperatures, and procedures for determining Mooney viscosity are defined in these test methods.
What will happen to the rubber if prolong mastication is taking place?
In the case of NR, the optimal NR viscosity was (at 0.1 Hz, 180°C), which was achieved by masticating for 12 min. However, a too-long mastication time (24 min) led to a dramatic decrease in both the impact strength and the % elongation at break due to fast shear-induced agglomeration of the low-viscosity rubber.
What chemicals are added to rubber?
Rubber Compounding
- Amine.
- Aniline.
- Butadiene.
- Carbon Black.
- Hysteresis.
- Phenolic Resins.
- Polytetrafluoroethylene.
- Styrene.
What are the ingredients of rubber?
The main chemical constituents of rubber are elastomers, or “elastic polymers,” large chainlike molecules that can be stretched to great lengths and yet recover their original shape. The first common elastomer was polyisoprene, from which natural rubber is made.
What is the chemical name of rubber?
polyisoprene
The chemical name for natural rubber is polyisoprene. The monomer (meaning “one-part”) from which it is built is isoprene.
What are the components of rubber?
What is scorch in rubber?
Scorch is the premature vulcanization in which the. rubber compound becomes partly vulcanized before. the product turns to its final form and is ready for vul- canization.
What is Mooney value?
The value of Mooney viscosity decreases at the beginning, due to the decrease of the compound viscosity as temperature rises. After about 4 min, a minimum value is reached, which stays constant for a while. This value is indicated as MV.
What is rubber chemical formula?
Chemical Name and Chemical Formula of Rubber Isoprene (2-methyl, 13-butadiene) is the monomer of natural rubber. Natural rubber is the polymer of this isoprene, and its chemical name is ‘cis – 1,4 – polyisoprene.
What are 4 uses of rubber?
Uses of Rubber
- Rubber moulded products are widely used industrially (and in some household applications) in the form of rubber goods and appliances.
- Rubber is used in garden hoses and pipes for small scale gardening applications.
- Most of the tyres and tubes used in automobiles are made up of rubber.
What type of material is rubber?
Technically speaking, rubber is a natural polymer of Isoprene (usually cis-1,4-polyisoprene). It is hydrocarbon polymer occurring as milky latex in the sap of various plants and can also be made synthetically.
What is rubber formula?
It is made by the polymerization of isoprene (2 methyl-1, 3-butadiene) which has a chemical formula (C5H8) n and it is known as cis- 1, 4- polyisoprene.
What is type of rubber?
The two main categories of rubber are natural rubber and synthetic rubbers. Silicone rubber is often considered to be a third category. Today, there are many types of rubber, each of which is ideal for different applications. Companies like Custom Rubber Corp.
Does peptizer affect the mastication process of natural rubber/butadiene rubber?
Recently, the effect of peptizer in the mastication process of natural rubber/butadiene rubber has been investigated by using Vestenamer, Aktiplast 8, and Rhenosin 145.
How to obtain homogeneous compounding from natural rubber/butadiene rubber?
To obtain homogeneous compounding, mastication has to be prepared well. Recently, the effect of peptizer in the mastication process of natural rubber/butadiene rubber has been investigated by using Vestenamer, Aktiplast 8, and Rhenosin 145.
Can natural rubber and butadiene rubber be mixed in tread compound?
The objective of this study is to optimize the performance of the tread compound, by mixing of specified ingredients, such as Natural Rubber (NR) and Butadiene Rubber (BR) at various compositions, and also the type of carbon black as filler. The composition of NR and BR are used as follows 100:0; 95:5 and 85:15.