G.S.Dyakonov, I.Sh.Abdullin, E.б.Sergeeva

Kazan State Technological University

68, K.Marx str., Kazan, 420015, Russia

The problem of production of a superlight high tensile composite material on the basis of nanocrystalline multifilament fibres of high-strength modular polyethylene (HSMP) is solved. Experimental investigations are carried out on increase of durability of fibre connection with a matrix and impregnation improvement of interfilament spaces using a matrix by processing an initial fibre with non-equilibrium low-temperature plasma. A superlight high-strength material called polyethylene plastic is obtained.

High durability of a material is of primary importance for the structures building. To achieve high durability of structures from the engineering point of view means to provide simultaneously high resistance to plastic deformation and high resistance to fragile fracture for a long time. Today one of the most popular ways to achieve high durability of materials is production of composite materials (CM) reinforced by the fibres.

Production of CM on the basis of fibres is based on the assumption that the plastic material of a matrix transfers the imposed loading to the fibres by tangential forces acting at the interface. If the matrix modulus of elasticity is less than the fibre modulus, then the major part of applied stress is taken by the fibres, and the total composite durability is proportional to their volume content.

Strong bond at the fibre-matrix interface is necessary for effective transfer of external loading to the fibre and for engaging of all the elements of CM structure into operation. Therefore one of the basic problems of production of the reinforced CM with high specific properties is the management of physical and chemical interaction between the components at the interface.

Main objective of the given research is production of superlight high-strength CM on the basis of nanocrystalline multifilament fibres of high-strength modular polyethylene (HSMP). To achieve the given purpose the authors have solved the following interconnected problems:

-         increase of durability of fibre-matrix bond for transferring the load to the fibre;

-         preservation of initial high properties of fibres;

-         maximally full impregnation of interfilament spaces by a matrix;

-         distribution of a given amount of fibre in a composite according to the loadings and conditions of its application.

The assigned tasks were carried out using non-equilibrium low-temperature plasmas at certain modes of fibre processing. It is known, that high-frequency plasma modification of materials possesses a universal influence of this plasma, independent of the processed material nature. The material placed in plasma undergoes a number of simultaneous influences: by the charged and excited atoms, molecules, radicals, ultra-violet radiation, heat flux, electromagnetic fields.

At present a number of reviews on plasma technologies for materials processing are known for manufacture of the composites reinforced by the fibres. However, the greatest number of works is devoted to researches of processing by the plasma of aramid, carbon, and glass fibres.

The problems of increase of durability of HSMP fibre - matrix bond are solved with preservation of initial high fibre properties at maximally full impregnation of interfilament spaces with a matrix.

A light high-strength modular CM polyethylene plastic with specific properties surpassing the properties of popular constructional materials is obtained. High durability of a material is ensured by its reinforcing nanocrystalline high-strength modular polyethylene fibres made of super-high-molecular polyethylene, consisting of nanocrystallites (95-98%) with the sizes of 10-50 nm.

Uniqueness and innovation of the work is provided by application of low-temperature plasma for fibre activation. Plasma raises superficial energy of a fibre that allows to control the features of interaction at the fibre-matrix interface and strongly connect a fibre to a matrix. It allows receiving monolithic high-strength CM polyethylene plastic, 6-7 times surpassing in specific durability the metals, 2 times surpassing the fibreglasses, and 1.5 times surpassing the coal plastic.