Polypropylene high strength wire is widely used in the textile, medical, composite materials and other fields due to its excellent strength, acid and alkali resistance and anti-aging performance. The tensile strength of polypropylene high-strength filament is the core indicator for evaluating its performance, mainly affected by factors such as raw material characteristics, stretching process and post-treatment conditions.

1. Raw material melt index

The melt index (MI) reflects the molecular weight of polypropylene raw materials and directly affects the mechanical properties of the fibers. The higher the molecular weight (the lower the melt index), the greater the entanglement of the molecular chain, the less the interchain slip during the stretching process, and the fiber strength is significantly improved. Experiments show that under the same spinning temperature and stretching ratio, polypropylene high-strength filaments made from low melt index raw materials have higher strength.

2. Stretching ratio and orientation structure

The stretching ratio is the key to destroying the disordered structure of primary fibers and forming new oriented crystals. With the increase of the stretching ratio, the molecular chains are arranged more closely along the fiber axis, the crystallinity increases, and the density and strength increase simultaneously. For example, when the stretching ratio is increased from 5 times to 8 times, the fiber strength can increase by more than 30%. However, it should be noted that an excessively high stretching ratio may lead to an increase in the brittleness of the fibers.

3. Stretching speed and crystallization behavior

The stretching speed affects the orientation of the molecular chain and the crystallization efficiency. When the speed is too fast, the molecular chains lack sufficient time to rearrange, resulting in incomplete crystallization and a decrease in strength. Moderately reducing the speed can optimize the orientation distribution and enhance the strength. For instance, in one-step spinning, the stretching speed and the spinning speed need to be matched to avoid the lag effect weakening the performance.

4. Fiber diameter and crystallinity

Ultrafine polypropylene fibers (with a diameter < 1μm) exhibit higher strength and modulus due to their large specific surface area and few defects. Meanwhile, the molecular chains of highly crystalline fibers are arranged in an orderly manner, which can effectively resist external forces and significantly enhance their strength. Studies show that for every 10% increase in crystallinity, tensile strength can increase by 15% to 20%.

5. Optimization of post-treatment processes

The heat setting temperature and time have significant influences on the properties of fibers. If the temperature is too low (< 150℃), the crystalline structure cannot be stabilized; if it is too high (> 200℃), it may lead to the degradation of molecular chains. Optimizing the post-treatment process (such as controlling at 150-200℃ for 30-60 seconds) can balance strength and toughness.

The tensile strength of polypropylene high strength yarn is the result of the combined effect of multiple factors. By choosing low melt index raw materials, optimizing the stretching ratio and speed, controlling the fineness and crystallinity of the fibers, and combining with precise post-treatment processes, its mechanical properties can be significantly improved to meet the requirements of high-end applications.

Xuzhou Peace Chemical Fiber Co., Ltd. is located in Xuzhou, Jiangsu. It has focused on the research and development and production of polypropylene, high strength, high strength, high strength, high strength, anti-aging, acid and alkali resistant, etc., which also make polypropylene high strength. Wire can be applied to all aspects of our lives. Peaceful chemical polypropylene, manufacturers supply, complete products, high quality after-sales service, users can rest assured to buy. Peace chemical fiber also has a polypropylene industrial silk, polypropylene high strength wire, high-strength polypropylene wire, polypropylene high strength yarn, high-strength propylene, and hydrazine industrial wire.

You still want to know more product information, please contact: Mr. Wang 187 5178 8889 Website: http://www.xzhp.com/