The performance and use of HIPS
Hips has the dimensional stability of general purpose polystyrene (GPPS), and has better impact strength and rigidity.
The relative density of hips is 1.04 ~ 1.06, and the hot deformation temperature is 70 ~ 84 ℃. The tensile strength of hips is about 15 ~ 30MPa and the elongation is 35 ~ 60%. It increases with the decrease of temperature and the increase of strain rate, a little like rubber toughening system. Hips is a kind of viscoelastic solid, which will creep when exposed to constant tensile stress. Creep decreases with the increase of molecular weight and usually increases with the increase of rubber content. The creep behavior of hips strongly depends on the average molecular weight (MW). The bending strength is 29.4 ~ 50 MPa, the impact strength is 0.09 ~ 0.16 n / m, the Vicat softening point is 84 ~ 100 ℃, and the melt index is 2 ~ 9 g / 10 min. The heat resistance of hips components depends on their shape, production conditions, heat source type and heating duration, and is also affected by hips level.
When exposed to water, alkali and dilute inorganic acid, the properties of hips were not affected. It can be swelled by some organic solvents and dissolved by others, which is determined by the difference of dissolution parameters between continuous phase and solvent phase. Hips is particularly vulnerable to damage when exposed to chlorinated and aromatic hydrocarbons.
Causes of shock resistance
Impact resistant polystyrene is a kind of impact resistant polystyrene product produced by adding polybutadiene rubber particles into polystyrene. This polystyrene product will add micron sized rubber particles and connect polystyrene and rubber particles together by branching. When impacted, the stress at the tip of crack propagation will be released by relatively soft rubber particles. Therefore, the crack propagation is hindered and the impact resistance is improved.
Because of its convenience and low cost, hips is widely used in many appliances and industries. The major industries and markets include packaging, disposable products, appliances and consumer appliances, toys and entertainment products, construction products and decorations. The biggest single application of hips is packaging, especially in the food industry. The consumption of hips in the world exceeds 30%.