behind the massive development of the synthetic rubber were, it could be vulcanized easily, its low costs and enhanced performances like gas impermeability.
Since styrene butadiene rubber and butadiene rubber are widely used in tyre
manufacture they are the most widely consumed type of synthetic rubber. Acrylonitrile rubber is used to make oil resistant materials and the neoprene rubber is
known for its resistance to ageing and weathering, ozone attack and flame
retardancy. Another synthetic rubber chloroprene has excellent oil resistance,
thermal stability, flame resistance, ozone resistance and good mechanical
properties [1].
The main characteristics which make rubber of great importance to the technology are its strength, the adhesion and strength of its bonding to metals and other
substrates. The elasticity or deformability enables it to be used in extension,
compression, shear, torsion or combinations of these. Rubber is easy to mold in
to any shape and size due to its resilience, resistance to fatigue and abrasion and
resistance to attack by corrosive chemicals. The rubber technologists are however
facing challenges in developing materials applicable in high temperature conditions, nuclear radiation, ablation in the rocket industry and mechanical abuse in ore
mining industries, oil well industries etc. The usefulness of rubbers in the industries
has three main reasons of which the first is its usability in the variety of environments, deformity and durability and possibility of convenient equipment designs.
Rubber is a good construction material especially for chemical plants as they resist
corrosion against chemicals, acids and alkalies. The third reason is its easiness to
convert to usable products readily and rapidly at a relatively lower cost [5–8].
1.2 Towards Rubber Properties
Rubber comes in the category of elastomers and according to Berins [2] an
elastomer is capable of rapid elastic recovery after being stretched to at least
twice its length at room temperature at any humidity. Due to the ease of deformation [3], softness and hardness, rubbers resist corrosion and erosion and have equal
importance as that of steel. Rubbers exhibit excellent properties like low thermal
expansivity and the properties become more pronounced during vulcanization or
interlinking by sulphur. The structure of rubber is a 3D zigzag with freely rotating
bonds that allow the polymer chains to change their length by coiling or uncoiling.
During heating the rubber chains rotate freely and thus coil or uncoil without
changing the internal energy unlike most solids which expand in volume upon the
application of thermal energy. This allows stretching and un-stretching of the
rubber without any change in the internal energy. However upon stretching rubber
experiences a restoring force, which is entropic in nature (as rubber pulls back to a
disordered state at maximum entropy). Stretching align the rubber chains into a
more ordered state with lower entropy [6].
In elastomers weak intermolecular forces exist and they undergo immediate,
linear and reversible response to high strain to an applied force. This response is
Origin of Nonlinear Viscoelasticity in Filled Rubbers: Theory and Practice
3
Since styrene butadiene rubber and butadiene rubber are widely used in tyre
manufacture they are the most widely consumed type of synthetic rubber. Acrylonitrile rubber is used to make oil resistant materials and the neoprene rubber is
known for its resistance to ageing and weathering, ozone attack and flame
retardancy. Another synthetic rubber chloroprene has excellent oil resistance,
thermal stability, flame resistance, ozone resistance and good mechanical
properties [1].
The main characteristics which make rubber of great importance to the technology are its strength, the adhesion and strength of its bonding to metals and other
substrates. The elasticity or deformability enables it to be used in extension,
compression, shear, torsion or combinations of these. Rubber is easy to mold in
to any shape and size due to its resilience, resistance to fatigue and abrasion and
resistance to attack by corrosive chemicals. The rubber technologists are however
facing challenges in developing materials applicable in high temperature conditions, nuclear radiation, ablation in the rocket industry and mechanical abuse in ore
mining industries, oil well industries etc. The usefulness of rubbers in the industries
has three main reasons of which the first is its usability in the variety of environments, deformity and durability and possibility of convenient equipment designs.
Rubber is a good construction material especially for chemical plants as they resist
corrosion against chemicals, acids and alkalies. The third reason is its easiness to
convert to usable products readily and rapidly at a relatively lower cost [5–8].
1.2 Towards Rubber Properties
Rubber comes in the category of elastomers and according to Berins [2] an
elastomer is capable of rapid elastic recovery after being stretched to at least
twice its length at room temperature at any humidity. Due to the ease of deformation [3], softness and hardness, rubbers resist corrosion and erosion and have equal
importance as that of steel. Rubbers exhibit excellent properties like low thermal
expansivity and the properties become more pronounced during vulcanization or
interlinking by sulphur. The structure of rubber is a 3D zigzag with freely rotating
bonds that allow the polymer chains to change their length by coiling or uncoiling.
During heating the rubber chains rotate freely and thus coil or uncoil without
changing the internal energy unlike most solids which expand in volume upon the
application of thermal energy. This allows stretching and un-stretching of the
rubber without any change in the internal energy. However upon stretching rubber
experiences a restoring force, which is entropic in nature (as rubber pulls back to a
disordered state at maximum entropy). Stretching align the rubber chains into a
more ordered state with lower entropy [6].
In elastomers weak intermolecular forces exist and they undergo immediate,
linear and reversible response to high strain to an applied force. This response is
Origin of Nonlinear Viscoelasticity in Filled Rubbers: Theory and Practice
3