Dynamics of Poly (butyl acrylate) and Poly (ethyl acrylate) with internal double bonds

Effect of Phenolic Resin Oligomer Motion Ability on Energy Dissipation of Poly (Butyl Methacrylate)/Phenolic Resins Composites

Poly (butyl methacrylate) (PBMA) was blended with a series of phenolic resins (PR) to study the effect of PR molecular weight on dynamic mechanical properties of PBMA/PR composites. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) found a similar variation of glass transition temperature (T_g). The maximum loss peak (tanδ_max) improved in all PBMA/PR blends compared with the pure PBMA. However, tanδ_max reduced as the molecular weight increased. This is because PR with higher molecular weight is more rigid in the glass transition zone of blends. The hydrogen bonding between PBMA and PR was characterized by Fourier transform infrared spectroscopy (FTIR). Lower molecular weight PR formed more hydrogen bonds with the matrix and it had weaker temperature dependence. Combined with the results from DMA, we studied how molecular weight affected hydrogen bonding and thus further affected tanδ_max.

Damping Analysis of Some Inorganic Particles on Poly(butyl-methacrylate)

Viscoelastic polymers can be used as damping materials to control unexpected vibration and noise through energy dissipation. To investigate the effect of an inorganic filler on damping property, a series of inorganic particles, Ferriferous oxide(Fe₃O₄), Graphene/Fe₃O₄(GF), and Fe₃O₄ of demagnetization(α-Fe₂O₃) were incorporated into poly(butyl-methacrylate) (PBMA). The effects of the dispersion of particles, as well as the interaction between particles and the PBMA matrix on the damping property of composites, were systematically studied. Results revealed that the addition of three types of particles can effectively improve the damping properties and broaden the effective damping temperature range. Dispersion of α-Fe₂O₃ in the PBMA matrix is better than that of Fe₃O₄. As a result, the damping peak can be increased more. The interaction between GF and the PBMA matrix is stronger than that between Fe₃O₄ and the PBMA. The damping peak of the composites can be suppressed by GF, which is opposite to Fe₃O₄ and α-Fe₂O₃. In addition, glass transition temperature (T_g) of all composites in the study shifted to low temperatures.

Improving Thermo-Oxidative Stability of Nitrile Rubber Composites by Functional Graphene Oxide

Graphene oxide (GO), modified with anti-aging agent p-phenylenediamine (PPD), was added into nitrile rubber (NBR) in order to improve the thermo-oxidative stability of NBR. The modification of GO and the transformation of functional groups were characterized by Fourier transform infrared spectroscopy (FTIR), Raman, and X-ray diffraction (XRD). Mechanical performances of NBR composites before and after the thermo-oxidative aging were recorded. The results of dynamic mechanical analysis (DMA) show an increased storage modulus (G’) and a decreased value of area of tan δ peak after introducing modified GO into NBR. It indicates that filler particles show positive interaction with molecular chains. The thermo-oxidative stability of composites was investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Then, the thermo-oxidative aging kinetic parameters were obtained by the Flynn–Wall–Ozawa (FWO) equation. The results of aging tests show that the thermo-oxidative stability of rubber matrix increases obviously after introducing GO–PPD. In addition, mechanical properties (tensile strength and elongation at break) of both before and after aged NBR/GO–PPD composites were superior to that of NBR. This work provides meaningful guidance for achieving multifunction thermo-oxidative aging resistance rubber composites.

Crystallization and molecular dynamics of ethylene-vinyl acetate copolymer/butyl rubber blends

In this article, butyl rubber (IIR) was blended with ethylene-vinyl acetate copolymer (EVA) through a molten method. In the blends, IIR is beneficial to the crystallization of EVA, while EVA confined the molecular motions of IIR.