Experimental study on the effect of fillers on the

Experimental study of filler on mechanical properties of PE microporous film continued

2. Results and discussion

2.1 effect of filler on mechanical properties of PE microporous film

Fig. 3 is the relationship curve between filler content and longitudinal tear strength of PE microporous film sample. It can be seen from Figure 3 that the longitudinal tear strength of PE microporous film sample decreases with the increase of filler content. For calcium carbonate and starch, the tear strength decreases rapidly when the filler content is small; When the content is large, it decreases slowly. Kaolin makes the longitudinal tear strength of PE microporous film decrease linearly

Figure 4 shows the relationship between filler content and transverse tear strength of PE microporous film sample. It can be seen from Figure 4 that with the increase of filler content, the transverse tear strength of PE microporous film sample decreases, especially the influence of kaolin

the relationship curve between filler content and film tear strength in figures 3 and 4 shows that the addition of filler will reduce P8 and place the clamp joint in a dry and clean place; E tear properties of microporous films. Among the three fillers of calcium carbonate, kaolin and starch, starch has the least effect on the longitudinal and transverse tear strength of PE microporous film, followed by calcium carbonate and kaolin

Fig. 5 is the relationship curve between filler content and longitudinal tensile strength of PE microporous film sample. As can be seen from Fig. 5, the longitudinal tensile strength of the film decreases with the increase of filler content

Fig. 6 is the relationship curve between filler content and transverse tensile strength of PE microporous film sample. It can be seen from Figure 6 that the transverse tensile strength of PE microporous film sample decreases with the increase of filler content

comparing Fig. 5 and Fig. 6, it can be seen that the filler has a significant impact on the longitudinal and transverse tensile strength of PE microporous film, and the variation trend of longitudinal and transverse tensile strength with the filler is basically similar, that is, the system containing calcium carbonate and kaolin changes approximately linearly, while the system containing starch changes slowly, especially at high content, the tensile strength of the system containing starch is higher than that of the system containing calcium carbonate and kaolin

2.2 effect of filler on moisture permeability of PE microporous film

Fig. 7 is the relationship curve between filler content and average moisture permeability coefficient of PE microporous film sample. It can be seen from Figure 7 that the average moisture permeability coefficient of PE microporous film sample increases with the increase of filler content. When the filler is wet calcium carbonate, the average permeability increases slowly; When the filler is starch, the increase is faster. Starch has a great influence on the average moisture permeability of PE microporous film, which can be attributed to the fact that starch has more hydroxyl groups, which form hydrogen bonds with water molecules and are very easy to attract water molecules

2.3 effect of filler on the permeability of PE microporous film

Fig. 8 is the relationship curve between filler content and △ P/△ t of PE microporous film. As can be seen from Fig. 8, with the increase of filler content, the △ P/△ t value of PE microporous film increases, and basically increases linearly. Among the three fillers of calcium carbonate, kaolin and starch, the AO/△ t value of starch increased the most, followed by kaolin and calcium carbonate

2.4 effect of filler types on the microporous structure of PE microporous film

many factors affect the cell shape, cell diameter and distribution of PE microporous film. The effects of calcium carbonate and starch on the cell shape, cell diameter and distribution of PE microporous film were studied

Figure 9 is the SEM photo of whether the PE micro inspection speed and rate are stable and normal pore film surface microstructure. The calcium carbonate content in Figure 9A is 11.5%; The starch content in Figure 9b is 12.3%

it can be seen from Figure 9 that under similar content, the bubble size on the surface of PE microporous film containing starch is large, the dispersion state of filler is poor, and more perforations are formed around starch particles. Calcium carbonate is evenly dispersed in PE microporous film, and the cell size on the surface is small

Fig. 10 is an SEM photograph of the cross-section microstructure of PE microporous film. Comparing Fig. 10a and Fig. 10B, it can be seen that the micropores of the two microporous film samples are irregular, narrow and long, and evenly distributed; PE microporous film containing 14.8% calcium carbonate has small microporous bubble size and is relatively dense; PE microporous film containing 14% starch has large microporous bubble size and is relatively sparse. Moreover, the shape of the microporous bubble in Fig. 10A is narrower and longer than that in Fig. 10B, and the gap between the microporous bubble and the bubble is smaller, even penetrating each other

3. Conclusion

(1) fillers such as calcium carbonate, kaolin and starch have a great influence on the properties of PE microporous films. With the increase of filler content, the tear strength and tensile strength of PE microporous film decrease, while the moisture permeability and air permeability increase. Among them, starch has the greatest influence on the moisture permeability and air permeability of PE microporous film

(2) filler has a great influence on the film formation of PE, and a small amount of filler also has a great influence on the film formation of PE. Among the three fillers of calcium carbonate, kaolin and starch, calcium carbonate has the best film-forming property

(3) the micropore shape of PE microporous film prepared by ordinary blown film method is narrow and long, and some of them are distributed in interconnected structure, and this structure changes with the processing technology. (text/Wu Zhihua, Liu Zhimin, Meng Bing)