Search

Poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/Nylon 66 blends have been considered as the potential heat resistant engineering plastics with high mechanical toughness and flame retardancy, suitable for high temperature applications. However, incompatibility between PPE and Nylon 66 and poor thermal stability of Nylon 66 degrade mechanical toughness and flame retardancy. In this work, for the first time, the PPE/Nylon 66 blends with high mechanical toughness and flame retardancy simultaneously have been prepared through newly synthesized compatibilizer of PPE grafted with fumaric acid (PPE-g-FA) and environmental-friendly non-halogen organic phosphinate flame retardant. The PPE/Nylon 66 blend achieved not only V0 grade flame retardancy with the help of improved fire resistance through the solid phase reaction of non-halogenic flame retardant, but also large impact strength larger than 10 kJ/m2 due to the strong compatibility of PPE-g-FA.

Heteroleptic ruthenium-complexed ladder-like structured polysilsesquioxane (LPSQ-Ru) was synthesized by post coordination reaction of bidentate ligand side chains in LPSQ with reactive Ru(II) complexes, which was well characterized by 1H and 29Si NMR, FT-IR, and spectroscopic techniques. The photophysical properties of LPSQ-Ru were examined by UV and PL analyses in both solution and solid states, comparing to analogous polymers of ruthenium-complexed polystyrene (PS-Ru). Obtained absorptions of LPSQ-Ru and PS-Ru were broadened ranging from 390-490 nm regardless of the states. However, LPSQ-Ru exhibited higher and shaper PL emission spectrum in comparison to that of PS-Ru, particularly in the solid state, because Ru-complexes in LPSQ were much effectively isolated, preventing their aggregations due to the rigid double strained siloxane backbone. This extinguished photophysical property in LPSQ-Ru kept after intensive thermal treatment at 250 °C for 90 min, which was not achieved in PS-Ru (~5-fold decrease). These differences originated from the backbone structures were also appeared in electrochemical properties in the solid states.

A ladder-like structured poly(mercaptopropyl)silsesquioxane (LPMPSQ) was synthesized in one-bath, under mildly basic conditions at room temperature. Obtained LPMPSQ was utilized as a macroinitiator for thiol-ene graft photopolymerization of various vinyl monomers to give hard, soft, hydrophobic, and hydrophilic graft copolymers with low PDI (

Designing topographic clusters is of significant interest, yet it remains challenging as they often lack mobility or deformability. Here we exploit the huge volumetric expansion (up to 3000%) of a new type of building block, thermally expandable microbombs. They consist of a viscoelastic polymeric shell and a volatile gas core, which, within structural confinement, create micro-clusters via inverse jamming and topographical close-packing. Upon heating, microbombs anchored in rigid confinement underwent balloon-like blowing up, allowing for dense clusters via soft interplay between viscoelastic shells. Importantly, the confinement is unyielding against the internal pressure of the microbombs, thereby enabling self-assembled clusters, which can be coupled with topographic inscription to introduce structural hierarchy on the clusters. Our strategy provides densely packed yet ultralight clusters with a variety of complex shapes, cleavages, curvatures, and hierarchy. In turn, these clusters will enrich our ability to explore the assemblies of the ever-increasing range of microparticle systems., Self-assembled systems are normally composed of incompressible building blocks, which constrain their space filling efficiency. Yu et al. show programmable, densely packed clusters using thermally expandable soft microparticles, whereby the self-assembling process is realized via a jamming transition.

A series of azido-functionalized ladder-like structures was prepared by direct azidation of ladder-like structured poly(p-chloromethylphenyl)silsesquioxane (LPCMPSQ) and poly(chloropropyl)silsesquioxane (LPAPSQ) in excellent yields with perfect substitution of the chloro-compounds. The azido-functionalized silsesquioxanes obtained were then photocured without additional photoinitiator to give highly cross-linked thin films with an exceptionally high modulus (> 12 GPa). Furthermore, these materials were shown to be patterned through photolithography to give impeccable micropatterned microstructures.

Poly(propyl carbazole silsesquioxane) (PPCSQ) with a high molecular weight (M w = 10,200) was synthesized by the direct hydrolysis of 9-[3-(trimethoxysilyl) propyl]-9H-carbazole with K2CO3, followed by a condensation reaction in an H2O/dimethylformamide (DMF) mixture solvent at 25 °C. The obtained PPCSQ consisted of ladder-like structured siloxane bonds with carbarzole groups as the pendant group, where the distance between two carbarzole pendant groups through the siloxane backbone was 15.6 A and the mean thickness of the siloxane backbone was 4.3 A. This PPCSQ was thermally stable up to 450 °C and the glass transition temperature was ca. 95 °C, showing good film formablity by spin casting.

A high molecular weight, photocurable inorganic-organic hybrid based on ladder-like poly(phenyl6-co-methacrylate4)silsesquioxanes (LPPMA64) was investigated as a flexible display substrate. Photocured free standing films with 40μm thickness showed high transparency (>95%), excellent thermal stability (Td >450°C), and low coefficient of thermal expansion (38ppm/K) without the use of reinforced glass fibers. Furthermore, these ladder-like structured materials did not require any thermal treatment processes due to the negligible amounts of uncondensed groups, thus simplifying manufacturing processing. These novel hybrid films present an alternative to organic plastics as flexible electronic device substrates due to their excellent optical and thermal properties.