Behavior Research Of The Polyurethane Liner Material Aging

The liner is a layer of viscoelastic polymer coating that is can be firmly adhered to the insulating layer or the engine casing. The main function is to bonding and buffer the stress, both insulation and restricted role, to control the propellant charge in accordance with the design for the purpose of combustion. In practical application, requiring to be bonded firmly between lining layer and the insulating layer (or shell), the interface bonding of solid propellant. And after long term storage,its bonding strength can meet the design requirements, not debonding, no interface effect.This paper selects four temperature, polyurethane lining material for research on aging performance at50℃,60℃,70℃,80℃. Includes:1) Research of thepolyurethane liner for accelerating aging behavior and aging mechanism.2) Research of liner interf-ace aging properties and aging mechanism.This study uses the Fourier-transform infrared spectroscopy, differential scanning calorimetry, Universal material testing machine, and other methods of analysis and testing, the effect of temperature and time on the properties of polyurethane liner aging. Determination of the lining layer infrared spectrum, thermal analysis; density, sol content, tensile strength and elongation, the lining layer and the two insulating materials of interfacial shear strength parameters. The results show that:1) the lining layer thermal accelerated aging period, thermal accelerated aging on the liner aging properties of the impact is mainly reflected in the change of network structure of matrix adhesives. The changes of no more than two aspects:one is to cause cross-linking, two is the degradation of broken chain;2) The maximum tensile strength with aging time increases at first and then decreases. The same aging time, the higher the temperature, the more rapidly the rate of aging, the lower the maximum tensile strength;3)Elongation with aging time decreased. The same aging time, the higher the temperature, the more rapidly the rate of aging, the lower the extension rate;4) Hydroxyl terminated polybutadiene polyurethane be composed of hard segment and a soft segment. Hard segment is toluene disocyanate,The soft segment is hydroxyl terminated polybutadiene,Aging is the main principle of polyurethane chain weak bond breaking.the weak keys Hydroxyl terminated polybutadiene polyurethane is mainly C-N, C-O, C-H and C=C bond;5) Thermal decomposition reaction can be divided into two stages, the low-temperature phase and high-temperature stage, which corresponds to a different reaction mechanism. The low-temperature phase is mainly oxidative crosslinking reaction,the high-temperature stage is the degradation of broken chain reaction;6)Sol decreases with aging time increases at first and then decreases. The same aging time, the higher the temperature,the more quickly the rate of aging, the lower the sol content;7) Density was increased with the prolonging of time. The same aging time, the higher the temperature,the faster the rate of aging, the higher the density;8) the maximum shear strength with aging time increases at first and then decreases. The same aging time, the higher the temperature, the more rapidly the rate of aging, the greater the maximum shear strength of the rate of change.