What are the factors that affect the strength of polypropylene high-strength fibres?
1. The influence of melt index
The melt index of the raw material indicates to a certain extent the molecular weight of the raw material. Under the same process conditions, the amount of fiber increases. The degree of molecular entanglement is large, and the strength of the drawn fiber increases with the increase of molecular weight. When the molecular weight is low, slippage between molecular chains is easy to occur, which is manifested in the decrease of fiber strength. In the spinning process of polypropylene high-strength fibres, several raw materials with different melt indexes are used.
In the trial spinning process, it was found that under the same process conditions, the melt index of the raw materials was different, and the strength of the finished yarn was different, and showed a certain regularity.
Under the same spinning temperature, the same draw ratio and the same process parameters, the lower the melt index of the polypropylene chip, the higher the strength of the polypropylene high-strength fibre.
2. The influence of stretching ratio
The stretching process of the nascent fiber is to destroy the original structure of the nascent fiber and generate a new order structure. Under the action of tensile stress and thermal effect, the activity of the macromolecular segment is increased, and various structural units slide the fiber. Axial orientation gathers, rearranges, and adds new bonding points, so that more molecular chains of the fiber are in a particularly good stress-bearing state, and the regularity of the three-dimensional structure (ie crystallization) is generated. The fiber density increases with the increase of the stretching ratio. .
As the draw ratio increases, the strength of the fiber increases, and the draw ratio makes a greater contribution to the strength of the fiber.
Polypropylene high-strength fibre plays a very important role in our lives. Each product has a different purpose and exerts a different effect.
Polypropylene high-strength fibre can be widely used in the luggage webbing market. It has the advantages of high strength, anti-aging, abrasion resistance, acid and alkali resistance, etc., and its weight is relatively light, and it is widely used in woven geotextiles. Packing bags and fire hoses, safety belts and other fields.
What factors affect the streng
