PC / PMMA sheet production line filled with polyoxymethylene and calcium
DATE：2021/6/18 9:25:14 / READ： / SOURCE：This station
PC / PMMA sheet production line filled with polyoxymethylene and calcium carbonate
The impact toughness of POM Composites was studied by using TPU as toughening agent and CaCO as reinforcement agent. The impact toughness of POM Composites was higher than that of one step and nano CaCO; The composite material has better comprehensive properties than other materials, and larger dispersing blocks and some separate CaCO, particles [Fig. 6-22 ()] can be seen on the section. The addition of elastomer and inorganic nano filler is beneficial to obtain better toughening effect. When the amount of elastomer is about 10%, CaCO and 3%, the impact strength is increased by 3 times and the bending modulus is similar to that of pure POM. When the amount of CaCO in the masterbatch is low, the impact toughness of the material is improved, but the low or too high amount of the material can not get the ideal toughening effect. The fracture morphology of the material was studied under different caco: concentration in the master material. It can be seen that when the amount of CaCO in the master material is low, inorganic particles are almost invisible on the section, and black holes formed after the elastomer is etched off indicate that the elastomer is relatively rich at this time, and it can effectively cover the filler particles to form a core-shell structure, and the surplus elastomers are scattered in the matrix in a separate dispersion form, The structure of the system is formed, which is dispersed separately (mainly elastic) and core shell structure. Due to the existence of the elastic body, the system has certain toughening effect; With CaCO in the masterbatch; With the increase of the amount of material, there are more rings on the material section, and there are no black holes in the sphere. It shows that there is no surplus of the elastomer at this time, and only the core shell structure dispersed phase exists in the system. The impact energy of core shell structure is stronger than that of the elastic particles when subjected to external loading, and the thinner the shell, the higher the impact energy absorbed by the material; When the amount of masterbatch continues to increase, larger dispersing blocks and some separate scattered CaCO and particles can be seen on the section. It shows that when the amount of caco: is high, more elastic materials are needed to cover inorganic particles. The filler is more, the particles are easy to agglomerate, the size of the core becomes larger, and the core shell structure size formed correspondingly increases. When CaCO; When the amount of the increase of the elastic mass is not enough to completely cover the filler, the inorganic particles are dispersed in the matrix separately. At this time, the dispersion form of the system is the larger core-shell structure and the separate dispersion (mainly filler particles) coexist. This structure is easy to produce a large stress concentration point and the material performance is low. Pc/pmma sheet production line www.handern.comThe impact strength of the composite decreases with the increase of caco: particle size. For example, when the TPU dosage is 10%, the impact strength of nano caco: filled composite is 24kj/m, 140nmcaco: the impact strength of the composite is reduced to 14kj/m2, while the impact strength of micron grade has been reduced to 7.8kj/m, which is similar to pure POM. This is because the nano material is filled with rice grade CaCO, which is more conducive to the small-size core-shell structure, can absorb higher impact energy and get the composite with high toughness; With the increase of particle size, large-size core-shell structure can be formed, with a large stress concentration effect and low impact strength. Pc/pmma sheet production line www.handern.com
The brittle fracture morphology of POM / 10% TPU / 3% CaCO: composite was filled with different particle sizes. It can be seen that all kinds of CaCO can form the core shell structure; With the increase of caco: particle size, the core shell structure size will increase, and the thickness of the matrix layer increases obviously. This shows that nano CaCO can obtain small-size core-shell structure, while micro caco: forms large-size core-shell structure. When the material is impacted, the large-size dispersed phase becomes a large stress concentration point, and the silver grain can develop into cracks directly; At the same time, the thickness of the substrate increases, the stress field produced by adjacent particles can not produce interference superposition, brittle fracture occurs and the impact toughness is low. Pc/pmma sheet production line www.handern.com
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