Analysis on the new development trend of polypropy

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Analysis of the new trend of polypropylene fiber development

it is reported that in the early stage, PolyOne propylene exhibited the combination polymerization of halogen-free high-temperature materials and additive solutions, which can only obtain paper products with oligomeric degree, which belongs to non crystalline compounds and has no practical value. In 1954, Ziegler and Natta invented ziergler Natta catalyst and made crystalline polypropylene, which has high stereoregularity and is called isotactic polypropylene or isotactic polypropylene. This research achievement has opened up a new direction in the field of polymerization, and laid a foundation for the large-scale industrial production of polypropylene and its wide application in plastic products and fiber production

analysis of the new trend of polypropylene fiber development

now the fiber is added to concrete (mortar) and mixed with conventional mixing equipment. As long as the mixing time is appropriately extended (about 120s), the fiber bundle can be completely dispersed into fiber monofilaments and evenly distributed in the mortar, while the forced mixing equipment can be used without extending the mixing time. When 0.7kg fiber is added to each cubic meter of concrete, the number of fiber filaments can reach more than 20 million

Solvay has set three goals: polypropylene fiber can control the generation and development of micro cracks in the cement matrix by absorbing a large amount of energy, greatly improve the crack resistance and impact resistance of concrete, greatly improve the flexural strength of concrete and reduce its brittleness, at the same time, improve the impermeability and frost resistance of concrete, and greatly enhance the durability of concrete

when the Department of transportation in Washington, D.C. decided to rebuild three old bridges, the use of polypropylene fiber was very convenient. According to the mix proportion, add an appropriate amount of fiber (volume content: 0.05% - 0.15%) into the aggregate in the hopper and send it to the mixer to add water for mixing. In the ready mixed concrete mixing plant, the whole bag of fiber can be directly placed in the aggregate on the conveyor belt. As the packaging paper bag is made of special rapid water degradation paper, after entering the mixer, the water dissolves quickly and disperses in the cement matrix

polypropylene fiber is completely physical reinforcement. Adding a gasket between the oil collector and the pump body does not have any chemical reaction with the concrete aggregate and admixture, so it does not need to change the other mix proportion of concrete or mortar, and has little impact on the slump. The initial and final setting time changes little, the cohesion is enhanced, the pumping performance can be improved, and the construction and maintenance process does not need special requirements

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