Ultraviolet radiation two-step grafting method on surface of polyethylene fiber with ultrahigh molecular weight

Abstract

The invention relates to an ultraviolet radiation two-step grafting method on the surface of polyethylene fiber with ultrahigh molecular weight. The method comprises the following steps of: coating a photosencitizer on the surface of preprocessed polyethylene fiber with ultrahigh molecular weight; soaking the polyethylene fiber in a first grafting monomer solution; forming a surface dormant group by adopting ultraviolet radiation or direct illumination; then, soaking in a second grafting monomer solution; initiating a secondary monomer surface free radical grafting reaction by ultraviolet radiation or heating; and finally, post-processing. Compared with the prior art, the invention has the advantages that the polar group is introduced to the surface of the polyethylene fiber with ultrahigh molecular weight, the reaction is controllable, the grafting efficiency and the grafting rate are higher, the second monomer with higher reaction activity is grafted on a primary grafting basis, and the adhesive performance of a matrix and the polyethylene fiber with ultrahigh molecular weight is greatly improved.

Description

technical field [0001] The invention relates to a polyethylene fiber grafting method, in particular to a two-step grafting method of ultra-high molecular weight polyethylene fiber surface ultraviolet irradiation. Background technique [0002] Ultra-high-strength polyethylene fiber (UHMWPE), also known as extended-chain polyethylene fiber, is a high-performance fiber that appeared after carbon fiber and aramid fiber. It is made of ultra-high molecular weight polyethylene, through high-pressure solid-state extrusion method, plasticized melt spinning method, surface crystal growth method, super-stretching or partial super-stretching method, gel spinning-hot stretching method, etc. A high-performance fiber with high strength and high modulus prepared by the process. It also has a low density (density of 0.97g / cm 3 ), chemical corrosion resistance, fatigue resistance, cutting resistance, low temperature resistance, impact resistance, non-absorbent, good compatibility with organ...

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Problems solved by technology

[0007] (1) The chemical etching method, the disadvantage is that the pollution is large, and the mechanical properties of the fiber are greatly affected

[0008] (2) Corona treatment has the advantages of strong environmental protection, low cost, simple method, and less impact on mechanical properties, but the modification effect is easy to attenuate

[0009] (3) Low-temperature plasma treatment has the advantages of strong environmental protection, good modification effect, and simple method, but the cost is high, it is not easy to treat continuously, and there is also the problem of attenuation of modification effect

[0010] (4) Photografting modification. At present, the commonly used radiation source is ultraviolet light, which has the advantages of strong environmental protection, low cost, good modification effect, almost no effect on the mechanical properties of fibers, and the modification effect lasts for a long time, but The current photografting modification method is not easy to control, and there are many side reactions, the grafting efficiency is low, and the homopolymer is obviously

[0014] Chinese patent document CN1035308A discloses a method for improving the surface bonding performance of UHMWPE fibers, which uses plasma to treat the surface of ultra-high molecular weight polyethylene fibers, and the wettability and surface bonding of the modified fibers to common substrates The performance is greatly enhanced, but the cost of this method is high, and it is not easy to produce continuously, and improper operation will easily cause the decline of the mechanical properties of the fiber

[0015] U.S. patent document USP4870136 discloses a method for improving the surface bonding performance of ultra-high molecular weight polyethylene fibers. It first melts and mixes a certain proportion of UHMWPE powder, free radical initiators, silane compounds and diluents in a screw, and carries out Speed-up melt spinning, in the spinning stage, the silanization grafting reaction is initiated by heat, and the spun fiber is thermally stretched in the medium of extractant and crosslinking agent, and then placed in boiling water to complete the crosslinking reaction. The surface bonding performance of the modified fiber is greatly enhanced, but due to the presence of a large number of initiators and grafts, the fiber draw ratio is low, and the mechanical properties of the spun fiber are poor.

[0016] Chinese patent CN1693544A discloses a method for improving the surface bonding properties of ultra-high molecular weight polyethylene fibers. It first dissolves the polar polymer in the conventional extraction of ultra-high relative molecular weight polyethylene jelly fibers with a weight average molecular weight of 1 to 5 million. In the extraction agent, it is made to meet the extraction agent, and the ultra-high molecular weight polyethylene jelly fiber is extracted in the extraction agent for a certain period of time at a certain atmospheric pressure and a certain temperature, and then stretched to obtain a modified ultra-high molecular weight polyethylene fiber. After curing, the bonding performance of the fiber surface is greatly improved, but it has an impact on the mechanical properties

The results show that after corona treatment, the oxygen content on the surface of UHMWPE fiber increases, the number and types of oxygen-containing groups increase, the surface wettability is improved, and the interfacial bond strength (τs) between the fiber and the matrix increases by 535%. Short beam shear strength τ nol It has increased by more than 40%, but the bonding performance of the fiber surface treated by this method is easy to decay, and it is not easy to store for a long time

[0018] [Jieliang Wang, Guozheng Liang, Wen Zhao, Shenghua Lu, Zengping Zhang. Studies on surface modification of UHMWPE fibers via UV initiated grafting[J]. Applied Surface Science, 2006, 253(2): 668 -673] Through liquid-phase UV irradiation grafting of acrylamide (AM), it was found that the monofilament pull-out strength and interlayer shear strength of the UHMWPE fiber after grafting were greatly improved, and the epoxy resin ILLS reached 16.9MPa, and The interlayer shear strength of special vinyl resin reached 19.4MPa, but the reaction time of this method is longer

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