Recently, we reported the isothermal crystallization behaviors of poly(l-lactic acid) (PLLA) from melt and glassy states, respectively [J. Phys. Chem. B 2004, 108, 11514; Macromolecules 37, 6433]. Surprisingly, quite different infrared (IR) spectral evolutions occur in two processes at temperatures which same crystal modification is expected to be formed. To clarify this unusual phenomenon, modifications thermal behavior PLLA samples prepared under are investigated detail by TEM, WAXD, FTIR...

The present study is aimed at investigating structure, dispersibility, and crystallinity of poly(3-hydroxybutyrate) (PHB) poly(l-lactic acid) (PLLA) blends by using FT-IR microspectroscopy differential scanning calorimetry (DSC). Four kinds PHB/PLLA with a PLLA content 20, 40, 60, 80 wt % were prepared from chloroform solutions. Micro-IR spectra obtained different positions PHB film are all very similar to each other, suggesting that there no discernible segregated amorphous crystalline...

By an ice-template method, in this work we realized ambient pressure dried graphene aerogel (ADGA) with superelasticity and multifunctionality by using ordinary instruments.

A detailed analysis of the IR spectrum melt-quenched PLLA−PEG−PLLA sample and its change with temperature is presented. It was found that, in initial state sample, PLLA constituent does not exist as a normal amorphous or crystalline phase but kind mesophase, which confirmed by WAXD data. The data suggest that both chain conformation packing are disordered to some extent such mesophase. Therefore, this mesophase less thermally stable than ordered α even (α′) PLLA. In heating process,...

Iridescent films formed from the self-assembly of cellulose nanocrystals (CNCs) are brittle and difficult to handle or integrate within an industrial process. Here we present a simple approach prepare iridescent CNC with tunable pliability coloration through addition ionic liquids (ILs) 1-allyl-3-methylimidazolium chloride (AmimCl) as plasticizers. By using undried film filter membrane ILs solution leaching liquid, it was found that filtration process made uniformly interpenetrate into due...

Iridescent films formed from the self-assembly of cellulose nanocrystals (CNCs) are brittle and difficult to handle or integrate within an industrial process. Here we present a simple approach prepare iridescent CNC with tunable pliability coloration through addition ionic liquids (ILs) 1-allyl-3-methylimidazolium chloride (AmimCl) as plasticizers. By using undried film filter membrane ILs solution leaching liquid, it was found that filtration process made uniformly interpenetrate into due...

Iridescent films constructed by self-assembly of rod-like cellulose nanocrystals (CNCs) are mechanically brittle and poor thermal stability. Herein, we demonstrate that the toughness stability vacuum filtered CNC iridescent could be significantly improved a simple alkali treatment. The results reveal NaOH treatment can simultaneously alter condensed physical structure surface chemical CNCs in their liquid crystal state while self-assembled chiral nematic is still well retained. To specific,...

Nitrogen-enriched (N-enriched) carbon nanofiber aerogels (NCNAs) with an ultrafine network structure were designed and prepared by using chitin as the precursor. Because of uniform nanofibrous architecture nitrogen-rich composition aerogels, NCNAs exhibited large specific surface area (490–1597 m2 g–1) a high nitrogen content (2.07–7.65%). As consequence, supercapacitor electrodes from NCNA-900 showed capacitances 221 F g–1 at current density 1.0 A good capacitance retention 92% over 8000...

A rapid and high-yield (up to 85%) preparation of a zwitterionic chitin nanofiber (DE-CO-ChNF) has been demonstrated.

Carboxylated cellulose nanocrystals (CNCs-COOH) have attracted great attention for their potential applications in reinforcing polymer materials and surface modification. Herein, we developed a low-cost approach to prepare CNCs-COOH from pulp with high yield at mild reaction conditions (50 °C, 1 wt % sulfuric acid medium) using potassium permanganate (KMnO4) oxalic (OA, H2C2O4) as the oxidizing reducing agents, respectively. The oxidant dosage this strategy is much lower than that...

Graphene aerogel (GA) has attracted great attention due to its unique properties, such as ultralow density, superelasticity, and multifunctionality. However, it is a challenge develop superelastic fatigue-resistant GA (SFGA) with density because generally contradictory improve the mechanical properties reducing of GA. Herein, we report simple efficient approach prepare ultralight SFGA templated by graphene oxide liquid crystal (GOLC) stabilized air bubbles. The thus-prepared (∼2 mg cm-3)...

Poly(vinylidene fluoride) (PVDF) is one of the polymers which exhibit pronounced polymorphic crystalline forms, depending on crystallization conditions. Four different modifications, i.e., α, β, γ, and δ, have been reported so far. Among them, even though α-form most common one, β-phase that has attracted widest interest due to its extensive piezo- pyroelectric applications. During past few decades, a substantial amount work done in attempts characterize these crystal modifications...

Poly(3-hexyllthiophene) (P3HT) with high crystallinity was prepared by controlling the solvent evaporation rate together aid of chloroform vapor annealing. According to infrared spectroscopy combined thermal analysis and X-ray diffraction (XRD) data, a new crystal modification named as form I′ identified for P3HT sample crystallized under extremely slow at low temperature (13 °C). Such has shorter interlayer distance than that more common but disordered I P3HT. Moreover, it demonstrates...

The structural evolutions and kinetics of melt-quenched poly(l-lactic acid) (PLLA) during the process isothermal physical aging below glass transition temperature (Tg) were investigated by time-resolved infrared spectroscopy. results show that local ordered structure is developed with time. Such shows same characteristic band at 918 cm–1 as mesomorphic formed unaxially drawn PLLA from glassy state. On basis spectroscopic evidence, we therefore proposed so-called can be ascribed to a kind...

Multifarious wearable electronics with flexible touch screens have been invented for extensive outdoor activities. One challenge associated these is the development of materials both high dielectric permittivity and anisotropic light transmission, which responsible sensitivity screen peep-proof protection, respectively. Herein, we demonstrated a scalable approach assembling aligning cellulose in polymer matrix through thickness direction via assistance an electric field to address this...

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTDepletion-Induced Nonbirefringent Banding in Thin Isotactic Polystyrene FilmsYongxin Duan, Yong Jiang, Shidong Lin Li, Shouke Yan, and Jerold M. SchultzView Author Information State Key Laboratory of Polymer Physics Chemistry, Institute Chinese Academy Sciences, Beijing 100080, P. R. China Department Chemical Engineering, University Delaware, Newark, Delaware 19716 Cite this: Macromolecules 2004, 37, 24, 9283–9286Publication Date (Web):October 30,...

The preparation of poly(l-lactic acid) (PLLA) foam with well-defined cell structure and high heat resistance is critical to broaden its applications. In this study, the stereocomplex crystallites (SC) higher melting point stability were introduced into PLLA by melt blending different amounts poly(d-lactic (PDLA). crystal structures pure PLLA/PDLA blends formed during molding process compared. It was found that no obvious crystallization detected in PLLA, while SC blends. Crystal morphology...

Graphene aerogel (GA) as a rising multifunctional material has demonstrated great potential for energy storage and conversion, environmental remediation, high-performance sensors or actuators. However, the commercial use of GA is obstructed by its fragility high cost. Herein, simple stirring-induced foaming mixed aqueous solutions natural rubber latex (NRL) graphene oxide liquid crystal (GOLC), we obtained tough, ultralight (4.6 mg cm-3), compressibility (>90%), water-adhesive graphene/NRL...

By using the in-situ reflection−absorption infrared technique, glass transition temperatures of poly(ethylene terephthalate) thin films were determined by detecting abrupt change in absorbance ratio two comparable bands at 1340 cm-1 (trans conformation) and 1370 (gauche during heating. It was found that Tg PET reduces with respect to bulk sample has a great dependence on film thickness. The conformational energy difference (ΔE) between trans gauche states each also calculated. results...

There has been intense interest in understanding the self-assembled structure of conductive polymer nanowires due to potential application photovoltaics area. In present study, free-standing poly(3-hexylthiophene) (P3HT) thin films consisting H-aggregated and recently reported J-aggregated (NWs) were respectively prepared by vacuum filtration method. The microstructure differences both samples studied detail combining multiple techniques, i.e., synchrotron radiation WAXD, solid-state NMR, IR...