The Semi-Interpenetrating Polymer Networks(Semi-IPNs) of poly(methyl methyacrylate/ethyl acrylate)(P(MMA/EA)) and polyurethane thermoplastic elastomer (PU) were synthesized by PU and copolymer of methyl methacrylate and ethyl acrylate to improve the compatibility of polymethyl methacrylate(PMMA) and PU Semi-IPNs . The structure and properties were investigated by Fourier transform infrared spectrometer, Solid nuclear magnetic resonance spectrometry, Dynamic mechanical thermal analysis and Mechanical properties. The tensile stress of (P(MMA/EA)/PU)( P(MMA/EA):PU=3:7) can get to 9.6MPa, the additional physical crosslinks and entanglement for Semi-IPNs are the reasons.
The rheological properties of HTPB mixed with boron (B) or agglomerated boron (TB) were investigated to explore the effect of the impurities of boron on the processing of propellant. The phase structure, morphology, and acidity of each sample were characterized by XRD, SEM and pH, respectively. The results show that rheological property of B/HTPB can be significantly improved by agglomerating boron with binder. Time has little effect on the viscosity of TB/HTPB while that of B/HTPB is a strong function of time. The viscosity of TB/HTPB decreases when the temperature increases from 303K to 343K, while that of B/HTPB decreases from 303K to 323K and then increases sharply after 323K. After agglomerating with binder, theTonsetof boron reduces from 1056K to 954K andTpdrops from 1076K to 998K. Compared with B2, the weight gain and oxidation degree of TB2 increases by 27% and 8.5%, respectively.
A method to evaluate the rheological properties of low density polyethylene (LDPE) using torque rheometer was developed and the parameter of Power rate model were obtained by fitting balance torque and balance temperature. The rheological parameters of polymer melts were evaluated on the basis of previous equation by introducing the apparent filling degree in torque rheometer, the results show the temperature compensated torque (Mtc) increase from 5.685 Nm to 6.972 Nm, while apparent filling degree change from 0.65 to 0.85 at the rotor speed of 29.98 rpm. TheMtcalso increase from 2,900 Nm to 3.528 Nm and increase by 0.628 Nm at the rotor speed of 4.985 rpm, while it increase by 1.287 Nm from 5.685 Nm to 6.972 Nm at the rotor speed of 29.99 rpm, which means the higher the rotor speed, the more influence on the torque. The other relative rheological parameters, such as the activation energy (ΔE), the Non-Newton (n), etc., calculated in this model, indicate the effect of apparent filling degree on the polymer melting rheology. The calculated values were compared with those derived from capillary rheolometer, the results show the apparent viscosity decrease with the increase shear rate in exponential function, the change rules of apparent viscosity are good agreement from two kinds test methods.
Gap-based polyurethane elastomer (GAPE) with different hard segment contents are synthesized with 44-Diphenylmethane diisocyanate (MDI), 1,4 butylene glycol (BDO) as hard segments and GAP as soft segments. Dynamic mechanical analysis (DMA) is applied to investigated the dynamic mechanical properties and the mechanical properties of GAPE are studied by materials laboratorial instrument. The results show that GAPE-2 with 33 wt% hard segment has better mechanical properties, of which the tensile strength is 11.3MPa and elongation at break is 460.5%.As shown in DMA, T g of GAPE-2 is-18.4°C, and the low-temperature fragility parameter and activation energy of GAPE-2 are lower, 55.6 and 271.0 KJ·mol-1 respectively. Elastomer with good stiffness and flexibility is obtained.
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