The thermomechanical behavior of polymer nanocomposites is mostly governed by interfacial properties which rely on particle-polymer interactions, particle loading, and dispersion state. We recently showed that poly(methyl methacrylate) (PMMA) adsorbed nanoparticles in poly(ethylene oxide) (PEO) matrices displayed an unusual thermal stiffening response. The molecular origin of this unique stiffening behavior resulted from the enhanced PEO mobility within glassy PMMA chains adsorbed on nanoparticles. In addition, dynamic asymmetry and chemical heterogeneities existing in the interfacial layers around particles were shown to improve the reinforcement of composites as a result of good interchain mixing. Here, the role of chain rigidity in this interfacially controlled reinforcement in PEO composites is investigated. We show that particles adsorbed with less rigid polymers improve the mechanical properties of composites.

Textural and energetic proprieties of kaolinite were studied by low-pressure argon adsorption at 77 K. The heterogeneity of four kaolinites (two low-defect and two high-defect samples) modified on their surface by cation exchange with Li+, Na+, or K+ was studied by DIS analysis of the derivative argon adsorption isotherms. The comparison between the derivative adsorption isotherms shows that the nature of the surface cation influences the adsorption phenomena on edge and basal faces. In the case of basal faces, two adsorption domains are observed: for the first one, argon adsorption is slightly sensitive to the nature of the surface cation; for the second one, argon adsorption energy depends on the nature of surface cation suggesting their presence on theoretically uncharged basal faces. This study also shows that the shape of elementary particles, as derived from basal and edge surface areas, changes with the nature of cation. This anomalous result is due to the decrease of edge surface area with increasing the size of the cation. This surface cation dependence can be accounted for the area occupied by the edge surface cations in the first argon monolayer.

Microporous polymers with rigid organic architecture offer a wide range of efficient on board hydrogen storage at low temperature. The fluoropolymers with intrinsic microporosity (MP1 and MP2) were synthesized and characterized. Characterization technique such as high resolution transmission electron microscopy (HRTEM) revealed that the highly stable microporous structure of MP2 was composed of nanoporous frame work which was further supported by the computational study. The high surface area and microporosity of the polymers were estimated by measuring the N 2 gas adsorption. The MP1 and MP2 exhibit BET surface areas 666 and 1050 m 2 /g respectively. The micropore size distribution curves show a higher concentration of subnanometer pores. The hydrogen storage capacity of the prepared polymers are promising and the performance relative to other microporous polymers is comparable.

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