PVC transverse heat shrinkable film production line
DATE：2021/5/28 8:44:58 / READ： / SOURCE：This station
PVC transverse heat shrinkable film production line
Blending modification of polyoxymethylene and polyethyleneCompared with POM, PE has better toughness and processability. Blending with POM can improve the processing performance, dimensional stability and impact strength of POM, and can produce alloy materials with rigid flexible combination and balanced comprehensive performance, which can be used for transmission parts of instruments. POM and LDPE. The compatibility of POM and LDPE was greatly improved by using compatibilizer (2-1). Figure 6-9 shows that with the increase of compatibilizer content, the tensile strength decreases slightly, but the notched impact strength reaches a peak value. When the content of Z-1 is more than 10%, the impact strength decreases rapidly, which is related to the analysis of morphology
It's consistent. PVC transverse heat shrinkable film production line www.handern.com
The amount of compatibilizer has a great influence on the coefficient of linear expansion. When the content of compatibilizer is less than 10%, the linear expansion coefficient decreases obviously, but when the content is more than 10%, the change is very small. The former indicates that the compatibility between the two is improved, the interfacial adhesion is increased, and the addition of interfacial compatibilizer makes the dispersed phase LDPE disperse uniformly, the spherulite of POM is refined, and the tensile strength is slightly decreased. However, the relationship between the notched impact strength compatibilizer amount (based on LDPE) and the mechanical properties of the blend system has a peak value, and the fluidity is increased, The coefficient of linear expansion decreases. Based on the analysis and test of the morphology, structure and properties of the blends, the optimal compatibilizer content (based on LDPE) is 5% ~ 7%. POM / LDPE Blends were prepared by blending LDPE and POM. When the content of LDPE is 10%, the friction coefficient of POM / LDPE Blends decreases from 0.30 of pure POM to 0.13 of the blends. The wear scar width decreases from 4.4mm of POM to 3.94mm. However, with the increase of LDPE content, the friction coefficient and wear scar width of the blends increase. It shows that excessive LDPE will lead to poor friction and wear properties of the blends, especially the effect of wear properties is more obvious. Because POM itself has high degree of bond, high hardness and good wear resistance, while LDPE has low degree of bond and low hardness, the addition of excessive LDPE will inevitably lead to the decrease of hardness of the blends, which will lead to the decrease of wear resistance of POM blends. SEM and FTIR analysis of the friction surface of POM and POM / LDPE Blends show that the LDPE in the blends transfers to the steel ring to form wear debris during the friction process, which effectively isolates the contact between the two friction surfaces, acts as a friction reducing and wear-resisting agent, significantly reduces the friction coefficient of POM resin, and improves the wear resistance of POM. Fig. 6-10 is a SEM photograph of the worn surface of POM. It can be seen from figure 6-10 that a large number of wear marks along the sliding direction show typical adhesive wear characteristics, indicating that under this condition, the wear of POM is mainly adhesive wear. PVC transverse heat shrinkable film production line www.handern.com
POM transfer film can be seen in the friction process. Under this friction condition, many parallel plough marks will appear on the POM surface along the friction sliding direction, and then plough cracks will occur in a short time. With the increase of friction time, irregular fusion between plough cracks will occur, which will cause large area of surface detachment and eventually lead to typical adhesive wear morphology on the POM wear surface. Fig. 6-11 is a SEM photograph of the worn surface of the blend with m (POM) / M (LDPE) of 90 / 10. Under the same conditions, except for a large number of fine debris, the wear characteristics of the blends are not obvious. There are many uneven wear marks in the sliding direction, and obvious plastic deformation appears at the edge of the wear marks. When the POM / LDPE Blend rubs against the steel ring, there is no transfer film on the surface of the steel ring, which is different from adding PTFE and other organic lubricants. Instead, some fine abrasive powder is distributed on the surface of the steel ring. It can be seen from Fig. 6-11 that some of the fine debris produced during the grinding of the steel ring and POM / LDPE Blend are pinched into flakes under the rolling of the steel ring, but most of them are pinched into fine particles. The existence of fine debris at the friction interface can effectively isolate the contact between the two friction surfaces and play the role of antifriction and wear-resistant agent, thus effectively improving the friction and wear properties of POM / LDPE Blends. PVC transverse heat shrinkable film production line www.handern.com
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