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Herein, acid-degradable poly(ortho ester urethanes) (POEUs) were synthesized via polycondensation between an acid-labile ortho ester diamine and active esters of poly(ε-caprolactone) (PCL) diols with different molecular weights. The POEUs nanoparticles were easily fabricated using an oil-in-water emulsion technique, whose ortho ester bonds in main-chains could be degraded at different rate in acidic...
Branching has been investigated in poly(acrylic acid) synthesized by conventional radical polymerization with and without chain transfer agent (CTA) at different temperatures and initial monomer concentrations. The average number of branches per monomer unit (i.e. degree of branching) was quantified by solution-state 13C NMR spectroscopy. The heterogeneity of branching (dispersity of the electrophoretic...
As the most important material of metalized capacitors, dielectric polymers with large energy density (Ue), promising discharging efficiency (η), and elevated breakdown strength (Eb) are dreadfully requested for energy storage purpose. During the charging and discharging circles, the Joule heat could cause significant temperature rising and undesirable early failure in the capacitors. Few of the known...
Polyamide 11 (PA11) nanocomposites reinforced with Cellulose Nanocrystals (CNC), dodecanoic acid surface modified CNC (CNC_d), and CNC with methyl laurate (CNC + ML) as plasticizer were fabricated. With the addition of CNC alone, tensile modulus and strength of the PA11 were improved, but the toughness decreased at high CNC concentration. Using CNCs that were surface modified, the tensile modulus...
A series of electron-acceptor polymers, copolymers and blends were used in all-polymer BHJ photodetectors and the effect of acceptor compositions on the key device parameters of dark current density and photocurrent was investigated. Compared with acceptor polymers and polymer blends, the devices based on acceptor copolymer showed lowered dark current and higher photocurrent, due to optimal molecular...
A polyelectrolyte membrane with anti-ultraviolet, anti-fouling, and antibacterial abilities was prepared using trimethyl quaternary ammonium salt grafting lignin (QAL) and polystyrene (PS) at different ratios. Contact angle measurements indicated that the addition of QAL into the PS blending membrane altered the hydrophilicity by trimethyl quaternary ammonium groups and phenolic hydroxyl groups of...
Two 4-pyridylthiophene monomers M1 (2,5-dibromo derivative) and M2 (5-bromo-2-iodo derivative) having the methoxy group at the 3-position were synthesized. The Grignard metathesis reaction of M1 using i-PrMgCl·LiCl demonstrated the highest monomer conversion (87%) and regioselectivity (GM1/GM1′ = 76/24). The following Kumada coupling polymerization by Ni(dppe)Cl2 gave P1-OMe with the number-averaged...
Electrospun nanofiber membranes (with varied fiber diameters and different membrane porosities and thicknesses) have been explored as innovative microfiltration media for the highly efficient and cost-effective removal of contaminations with particle sizes of 0.2 μm (even 0.1 μm) from water. For the first time, the membrane porosity has been judiciously adjusted/controlled by a facile hot-pressing...
Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) is utilized for gas separation membranes. It has a relatively high free volume with high gas permeabilities but suffers from low selectivities. PPO polymers with Mn's from 2000 to 22,000 g/mole were synthesized and blended with a poly(arylene ether ketone) derived from bisphenol A and difluorobenzophenone (BPA-PAEK). DSC showed that the blends with all...
Rapidly electro-active thermoplastic polyurethane (TPU)/polylactide (PLA) shape memory polymer (SMP) blends via phase morphology control and incorporation of conductive multi-walled carbon nanotubes (MWCNTs) were achieved by simple and efficient melt blending in this work. Binary TPU/PLA blends with various composition ratios were firstly prepared, and the effect of phase morphology on shape memory...
Segmented poly(urethane acylsemicarbazides) carrying aromatic groups in the hard segments were synthesized by two step polymerization technique using commercially available, cost effective raw materials. The resulting polymers with specific ratios of NCO/OH were found to gel organic solvents like dimethylformamide, dimethylacetamide and N-methylpyrrolidone and their corresponding gels were thermoreversible...
We study a three-dimensional (3D) liquid crystal elastomer (LCE) in the context of Finsler geometry (FG) modeling, where FG is a mathematical framework for describing anisotropic phenomena. The LCE is a 3D rubbery object and has remarkable properties, such as the so-called soft elasticity and elongation, the mechanisms of which are unknown at present. To understand these anisotropic phenomena, we...
Segmented imidazolium ionenes with poly (tetramethylene oxide) (PTMO) soft segments and ionic, bis-imidazolium hard segments formed nonwoven fibrous mats upon electrospinning. The segmented imidazolium ionenes exhibited high thermal stability, excellent mechanical properties, and two glass transition temperatures indicative of microphase separation. Tensile analysis revealed strain-induced crystallization...
A new mending chemistry exhibiting stability at extreme temperatures and holding mechanical properties as well as mechanical stability comparable to widely used engineering plastics is reported here. This mendable thermoset polymer is synthesized using commodity reactants through the formation of an isocyanurate-oxazolidone network which exhibit a high service temperature as shown by their Tg of 270 °C...
We present a novel family of biocompatible hydrogels containing Nafion and poly(ethylene oxide) based block copolymers. In aqueous environment, thermodynamically stable ionomer-copolymer complexes are formed, as evident by light scattering and quartz crystal microbalance experiments. Moreover, incorporation of Nafion dramatically modifies the phase behaviour and the rheological properties of copolymer...
Two kinds of ethylene-α-octene copolymers (ethylene-α-octene block copolymer, OBC, and ethylene-α-octene random copolymer, ORC) and their composites with MWCNTs were investigated by means of various solid-state NMR techniques. 13C MAS NMR revealed that there were only orthorhombic crystals in OBC composites, which resulted in stronger volume exclusion effect towards MWCNTs than that in ORC composites...
An intrinsic high-barrier and thermally stable polyimide (2,7-CPPI) was prepared by the polymerization of pyromellitic dianhydride (PMDA) and novel diamine (2,7-CPDA), which consists of rigid planar carbazole moiety. The resulted 2,7-CPPI exhibits excellent barrier properties, with oxygen transmission rate and water vapor transmission rate low to 0.2 cm3 m−2·day−1 and 0.1 g m−2·day−1, respectively...
The vast majority of latex particles, including those made from multiple polymers, are spherical in shape. This is a result of the minimization of the combined interfacial free energies at the polymer particle–water interface and the polymer–polymer interfaces within the particle. Yet there are special situations in which latex particles containing two, incompatible polymer phases can form asymmetric,...
A novel amphiphilic four-arm star copolymer [poly(ε-caprolactone)-b-poly(poly(ethylene glycol) methyl ether methacrylate-co-p-(2-methacryloxyethoxy) benzaldehyde)]4 [4-AS-PCL-P(PEGMA-co-MAEBA)] was designed and synthesized by a combination of ring-opening polymerization (ROP) and continuous activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Stimuli-responsive...
The mechanical properties of PPTA crystallites, the fundamental building blocks of aramid polymer fibers such as Kevlar® and Twaron®, are studied here using molecular dynamics simulations. The ReaxFF interatomic potential is employed to study crystallite failure via covalent and hydrogen bond rupture in constant strain-rate tensile loading simulations. Emphasis is placed on analyzing how chain-end...
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