Fabrication and mechanical properties of knitted dissimilar polymeric materials with movable cross-links

Abstract

Bulk polymerization of liquid main chain monomers in the presence of a linear polymer bearing acetylated γ-cyclodextrin (TAcγCD) (primary polymer) results in composite materials consisting of dissimilar polymer chains, hereinafter...

Preparation of mechanically tough poly(dimethyl siloxane) through the incorporation of acetylated cyclodextrin-based topologically movable cross-links

“…The R 2 value of CCPDMS when fitted over 6000 seconds (0.990) was smaller than that obtained until 600 seconds (0.997). Since the presence of movable cross-links based on TAcγCD shortens the relaxation time, 37,38 we discussed the relaxation behaviors focusing on the early stage by analyzing the fitting curves. The longer relaxation time of PDMS-TAcγCD-Pen(1) and PDMS-TAcγCD-Pen(3) compared with CCPDMS are logically unreasonable and support the suitability of the fitting within the initial 600 seconds.…”

“…As effective energy dissipation, sacrificial networks, [23][24][25][26][27] chain length distributions, 28 sliding motion of cross-links based on rotaxane structures, [29][30][31][32][33][34][35][36][37][38][39][40] appropriate relaxation behaviors, [41][42][43][44] and reversible dynamic bonds such as hydrogen bonds, [45][46][47] π-π interactions, 48 host-guest complexation, [49][50][51] coordination bonds, 52 and ionic bonds 53,54 have been reported in carbon-based materials. Among the numerous strategies described above, the incorporation of reversible dynamic bonds [55][56][57][58] and topological cross-links 59 have mainly improved the mechanical properties of PDMS materials.…”

“…As polymeric chains and TAcγCD are covalently connected, TAcγCD moves along the passing PDMS and vice versa . In addition, movable cross-links have been used to successfully mix generally immiscible polymers, such as polystyrene mixed with poly(ethyl acrylate) 37 and poly(dimethyl acrylamide) mixed with poly(ethyl acrylate- co -butyl acrylate). 43 We studied these tough PDMS elastomers in terms of mechanical properties and structures using tensile tests, cyclic tensile tests, stress relaxation tests, differential scanning calorimetry (DSC), and ultrasmall- and small-angle X-ray scattering (USAXS and SAXS) measurements.…”

Cyclic Polyphenylene Sulfide as Additive to Improve the Mechanical Properties of Polystyrene-Based Materials

“…Polyphenylene sulfide (PPS) is one of the most significant engineering plastics, but only linear PPS is in great demand and widely produced. − However, it is impossible to prevent the formation of cyclic PPS during polymerization to obtain linear PPS. − Cyclic PPS was only investigated in terms of its molecular structure and reactions in the 1990s. − Although the cyclic PPS has almost no usage in practical applications, it may have the potential to be used in supramolecular chemistry because it has a cavity and probably a π–π stacking effect according to its structure, which is similar to that of cyclodextrin and cucurbit­[ n ]­uril. − Thus, we propose that cyclic PPS could be another host used in supramolecular chemistry to improve the mechanical properties of polymers such as polystyrene (PS)-based materials. The application of PS and its composites is limited by their brittleness because of a high density of π–π stacking effect though the strength of that is about 10 kJ/mol. − To improve the mechanical properties of PS, additives such as soft polymers, inorganic clays or nanotubes, and organic additives are used to transfer energy from PS to a more flexible phase where the energy is dissipated. − …”

Hybridizing a Dual-Cross Network and a Linear Glassy Polymer for Dynamic Contributions to High Mechanical Toughness Based on Phase-Separated Structures

“…To reduce plastic wastes, tough polymeric materials have been of great interest for solving environmental issues. To enhance the toughness (work to fracture specimen; G f ) of polymeric materials, materials scientists have investigated polymer network design by using various approaches to avoid stress concentration. − Recently, polymeric materials with cross-linkers have been employed to establish new material designs for tough materials. − The introduction of movable cross-linkers is an effective method for improving the mechanical properties beyond those obtained with covalently cross-linked polymeric materials. When preparing a polymeric material with movable cross-linkers, cyclic molecules are required to penetrate the polymer chain. − Preorganized polyrotaxane is an effective polymer component with which to prepare movable cross-linked materials. − …”