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The preparation of hybrid proton conductive membranes that comprise of covalently linked interpenetrating polymer and inorganic networks is reported. The hybrid membranes are synthesized via simultaneous photo‐initiated polymerization and sol–gel processing. The simultaneous processing permeates fabrication of the membranes that comprises covalently cross‐linked polymeric and inorganic networks. The membranes are characterized by attenuated total reflectance‐Fourier transform infrared spectroscopy, scaning electron microsopy, thermogravimetric analysis, differential scanning calorimetry, in order to confirm their chemical composition, structure, and morphology. An addition of 3‐methacryloxypropyl trimethoxysilane into the sol–gel composition allows the formation of covalent linkages between polymeric and inorganic networks, which facilitates a uniform distribution of the molecular components across the fabricated membranes. The incorporation of the silica network leads to an increase in water retention and proton conductivity of hybrid membranes as compared to their purely polymeric analogues. [ABSTRACT FROM AUTHOR]

Strain steps are applied to elastomers in a pneumatic relaxometer and monitored by small‐angle X‐ray scattering (SAXS). The relaxometer provides a rise time of 13 ms for strain pulses of step height Δε = ±1 in strain. The basic character of the 2D SAXS frames is examined and corresponding invariants Q(t) are analyzed. Three thermoplastic polyurethanes (TPU) of hardness 85 Shore A with different soft segments are studied both unannealed and annealed. The first response of all materials is a fast morphology conversion which finishes within tmc =250 ms. Because it has been untraceable, it is characterized by a settling stroke Q(tmc) − Q(0). The second response is a slow morphology adjustment process which complies with logarithmic relaxation. It is characterized by a relaxation rate DQ = Q(10 t)/Q(t) − 1. Comparison indicates that the nanoscopic morphology relaxation processes appear to have little direct relation to the macroscopic stress relaxation curves. The materials differ with respect to hard‐domain morphology stability and morphology recovery. Most unstable is the morphology of the annealed polyether‐based material. It forms nanofibrillary entities when strained. [ABSTRACT FROM AUTHOR]

The influence of annealing on mechanical αc-relaxation of isotactic polypropylene ( iPP) is investigated. In the sample without annealing, polymer chains in the intermediate phase are constrained by crystallites with a broad size distribution, leading to one αc-relaxation peak with activation energy ( Ea) of 53.39 kJ mol−1. With an annealing temperature between 60 and 105 °C imperfect lamellae melting releases a part of the constraining force. Consequently, two αc-relaxation peaks can be observed (αc1- and αc2-relaxation in the order of increasing temperature). Both relaxation peaks shift to higher temperatures as annealing temperature increases. Ea of αc1-relaxation decreases from 38.43 to 35.55 kJ mol−1 as the intermediate phase thickness increases from 2.0 to 2.2 nm. With an annealing temperature higher than 105 °C, a new crystalline phase is formed, which enhances the constraining force on the polymer chains. So the αc1-relaxation peak is broadened and its position shifts to a higher temperature. Moreover, the polymer chains between the initial and the newly formed crystalline phase are strongly confined. Therefore, the αc2-relaxation is undetectable. Ea of αc1-relaxation decreases from 23.58 to 13.68 kJ mol−1 as the intermediate phase thickness increases from 2.3 to 3.0 nm. [ABSTRACT FROM AUTHOR]

The structure evolution of isotactic-polypropylene during creep is investigated by in situ synchrotron small-angle X-ray scattering. During primary creep, strain grows nonlinearly to a value less than 15%. The long period in loading direction ( L∥) increases with time, whereas the long period perpendicular to the loading direction ( L⊥) decreases slightly. During the secondary creep, strain increases linearly with time. L∥ and L⊥ show the same tendency with strain. The increase of the long period is caused by lamellae thickening, which is a kind of cooperative motion of polymer chains with their neighbors at the lamellae surface. Moreover, the growth rate of L∥ is larger than that of L⊥, indicating that the orientation of molecular chains along the loading direction decreases the energy barrier of the cooperative motion. During tertiary creep, strain grows dramatically in a short time. In this step, the lamellae are tilted, rotated, and then disaggregated. In addition, a fibrillar structure is formed during lamellae breaking. The length of the fibrillar structure increases from 364 to 497 nm while its width stays at 102 nm with increasing creeping time. [ABSTRACT FROM AUTHOR]

Front Cover: The microstructural evolution during creep is investigated by in situ synchrotron small‐angle X‐ray scattering, which could be well distinguished into four stages. During primary creep, strain grows nonlinearly to a value less than 15% is a short time because of elastic deformation. During secondary creep, lamellae thickening could be found. The lamellae thickening rate along loading direction is higher than that perpendicular to the loading direction, indicating that the orientation of molecular chains along the loading direction facilitates the lamellae thickening process. After yielding, the fibrillary structure could be induced by lamellae breaking‐reorganization. The length of the fibrillary structure increases from 364 nm to 497 nm, whereas its width stays at 102 nm as creep time increases. This is reported by Baobao Chang, Konrad Schneider and Gert Heinrich, in article number 1700152. [ABSTRACT FROM AUTHOR]