Water Resistance Of Insulation Strips

A good insulation strip has a dense internal structure. Under normal conditions, the density of the insulation strip can be easily determined by weighing the weight of each meter of insulation strip. Under a microscope, the glass fibers of the good polyamide insulation strip are evenly distributed, without defects such as bubbles or obvious inclusions; The distribution of inferior insulation strip glass fibers is relatively disorderly, accompanied by obvious defects such as bubbles and inclusions. Taking I14.8 as an example, a good insulation strip weighs around 45g per meter. Due to the hydrophilic amide group in the molecular structure of PA66, it has strong water absorption and significantly affects the mechanical properties of the material. Adding a special hydrolysis resistant agent MPP to glass fiber reinforced PA66 to improve its hydrolysis resistance, as MPP has a certain polarity and low water absorption, and three effects occur after adding MPP to PA66.

1. Polarity shielding effect: i.e., the polar group of MPP and the polar group of PA66 have a mutually reinforcing effect, thereby weakening the interaction between the polar group of PA66 and water.

2. Crystal shielding effect: In the blend of MPP and PA66, both are crystalline polymers, leading to co crystallization or grain wrapping, crossing, covering, and other effects, thereby weakening the interaction between water and PA66.

3. Structural shielding effect: In the blend, PA66 is a continuous phase and MPP is a dispersed phase, with strong interfacial bonding. The non polar long chain of MPP acts as a barrier to water, thereby hindering water penetration.

The addition of the three functions of the above insulation strips leads to a decrease in the water absorption of the blend, ultimately improving the hydrolysis resistance of PA66.