Phenyl Polymers Research Articles

Atomic Insights into the Relationship between Molecular Structure and Dispersion Performance of Phenyl Polymer on Graphene Oxide.

The adsorption of organic polymers onto the surface of graphene oxide is known to improve its dispersibility in cement-based materials. However, the mechanism of this improvement at the atomic level is not yet fully understood. In this study, we employ a combination of DFT static calculation and umbrella sampling to explore the reactivity of polymers and investigate the effects of varying amounts of phenyl groups on their adsorption capacity on the surface of graphene oxide. Quantitative analysis is utilized to study the structural reconstruction and charge transfer caused by polymers from multiple perspectives. The interfacial reaction between the polymer and graphene oxide surface is further clarified, indicating that the adsorption process is promoted by hydrogen bond interactions and π-π stacking effects. This study sheds light on the adsorption mechanism of polymer-graphene oxide systems and has important implications for the design of more effective graphene oxide dispersants at the atomic level.

Temperature induced helical contraction and expansion in branched polycarbodiimides and their solvent vapor sensing properties

Helical polycarbodiimides with either naphthalene or anthracene side chains display chiroptical switching properties in solution and the solid state. This interesting chiroptical switching occurs due to the expansion and contraction of the helical backbone and the simultaneous reorientation of the aromatic side chains. Herein, we modified the aliphatic side-chain structure to induce the switching behavior in simple phenyl substituted polycarbodiimides. The polymerization of 1-hexynyl-5-phenylcarbodiimide introduced a terminal alkyne appended to the polymer backbone. By using the CLICK reaction, we were able to attach steric bulky branched alkyl groups to poly(N-phenyl)-N′-(n-branched alkyl) carbodiimide (P-1B). To increase the solubility and modulate the aliphatic sidechain packing of the polymer, 1-hexynyl-5-phenylcarbodiimide was copolymerized with phenyl octadecyl carbodiimide in different mole ratios. IR spectra and Specific Optical Rotation (SOR) studies showed these simple phenyl polymers show temperature driven solution state switching between two and sometimes three conformational states akin to what was only previously observed in polymers with polyaromatic side chains. In addition, one of the copolymers, P-2B, synthesized from the 50/50 mole feed ratio of the branched monomer and phenyl octadecyl carbodiimide showed solid-state sensing of various volatile organic compounds (VOCs) and solvent vapor.

Application of magnetic adsorbent with silicate and phenyl polymers to adsorb Rhodamine B

The extensive use of Rhodamine B (RhB) for textile, paper, pigment, food, cosmetic, and drug manufacturing and its indiscriminate disposal leads to serious human, biological, and environmental hazards. A magnetic adsorbent with silicate and phenyl polymers (Ph/SiO2/Fe3O4) has been prepared to absorb RhB. The morphology and structure of the adsorbents have been characterized by TGA, XRD, FTIR, and adsorption–desorption measurement. The results revealed that Ph/SiO2/Fe3O4 exhibited a paramagnetic behavior and could easily and quickly be separated from a suspension. The RhB adsorption behavior was almost pH independent due to the adsorption between the phenyl ring of Ph/SiO2/Fe3O4 and RhB by π–π electron-donor–acceptor interactions. The adsorption behavior of RhB adsorption was in good agreement with the Langmuir adsorption isotherm, and the maximum adsorption capacity was 142.186 mg g−1. Good desorption performance of Ph/SiO2/Fe3O4 showed that this novel magnetic adsorbent cannot only be activated by ethanol extraction process but also reuse by the recovery of magnetic force.

The electronic structure of conjugated polymers

The density matrix renormalisation group (DMRG) method is a powerful computational technique for calculating the electronic and geometrical structures of one-dimensional conjugated polymers. First, we solve the Pariser-Parr-Pople-Peierls model for trans-polyene oligomers. We investigate the energies and solitonic structures. Next, we solve the Pariser-Parr-Pople model for the light emitting phenyl polymers, and ascertain the nature of the excited states. Finally, we discuss how the DMRG method can be extended to ZINDO and ab initio Hamiltonians, and to electron-phonon problems.

ALTERNATING COPOLYMERS CONTAINING AN AROMATIC CHROMOPHORE IN EVERY MONOMER UNIT. 2. EXCIMER FORMATION AND INTRAMOLECULAR ENERGY MIGRATION IN ALTERNATING COPOLYMERS OF NAPHTHYLALKYL METHACRYLATE AND VINYLNAPHTHALENE

A series of alternating and random copolymers of 2-naphthylal-kyl methacrylates (NpMMA and NpEMA) and 2-vinylnaphtha-lene (VNp) were synthesized, and their fluorescence properties in tetrahydrofuran (THF) were compared. All of the alternating copolymers containing NpMMA or NpEMA showed a weak ex-cimer emission, indicating that excimer formation between naph-thyl (Np) chromophores in the alternating methacrylate sequences cannot be perfectly inhibited. No distinct difference in the fluorescence from the NpMMA and VNp moieties in poly(NpMMA-alt-VNp) (a-NpVNp) suggests that practically the same chromophores are aligned along the whole polymer chain. This observation is sharp in contrast with the corresponding phenyl polymers exhibiting different spectral features. Fluorescence quenching studies, however, showed no enhancement of the quenching efficiencies for a-NpVNp among the pres-ent polymers. Therefore, energy migration between the nearest-neighboring Np chromophores would inefficiently occur, though this polymer has the highest density of chromophores.

Studies on the odd-even effect of methylene spacers in poly(pyromellitimide-ester)s

Three series of poly(pyromellitimide-ester)s were synthesized from various N,N′-bis(ω-hydroxyalkyl)pyromellitimides (HAPMIs) by melt condensation with dicarboxylic acids, including terephthalic acid (TPA), 4,4′-biphenyldicarboxylic acid (BPDA), and 4,4′-azobenzenedicarboxylic acid (ABDA). Polymers were characterized by elemental analysis, solubility, inherent viscosity, spectra (IR, 1H-NMR, 13C-NMR), and X-ray diffraction (XRD). Thermal stability and phase transition behaviour were evaluated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and hot-stage optical polarized microscopy (HOPM). The d-spacings, calculated from XRD data, showed an odd-even effect with varying numbers of methylene spacers. Crystallinity of polymers decreased in the following order: azobenzene > biphenyl > phenyl polymers. Similarly, DSC-obtained melting temperatures (Tm's) showed an odd-even effect, and glass transition temperatures (Tg's) decreased with increasing numbers of methylene spacers. Thermal stability decreased as methylene chain length increased. Thermal stability of polymers occurred in the following order: phenyl > biphenyl > azobenzene polymers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1755–1761, 1999

Safety of silicone liquid in the postoperative management of Dupuytren's contracture.

Recently the New Zealand Department of Health expressed concerns about the safety of applying silicones to open wounds and banned their use. For 30 years silicone liquid has been used for the management and rehabilitation of the injured hand. It has been reported that the application of silicone fluids to the skin and ordinary handling over a period of years of various methyl and phenyl polymers by laboratory workers caused no skin disorders or sensitization, nor was absorption observed. There are no reports in the literature of the safety of the use of silicones applied to open wounds. In the present study, 116 hands that had been mobilized in silicone liquid following surgery for Dupuytren's contracture over the last 12 years were reviewed. In the cases of 64 hands, the patients could be traced and contacted, and 47 patients (hands) agreed to attend for a clinical review. The hands were examined for areas of inflammation, granuloma formation and abnormal scar formation. No patient showed any evidence of adverse effects from the use of silicone liquid. There is no evidence that the use of silicone liquid, in contact with open wounds of the hands, for the mobilization of the hand following surgery for Dupuytren's contracture has any of the adverse effects reported as being associated with implanted silicone prostheses.

The preparation of non-extractable methylphenylpolysiloxane stationary phases for capillary column gas chromatography

The synthesis of methylphenylpolysiloxane polymers and their use in the preparation of crosslinked, non-extractable stationary phases for fused-silica capillary columns are described. By preparing more viscous phenyl-containing polymers than are commercially available, stationary phase films of these polymers could be efficiently coated on fused-silica capillary columns and stabilized by a free radical crosslinking mechanism using peroxides. Four methylphenylpolysiloxane polymers containing different phenyl concentrations were prepared. These included three polymers containing 50% phenyl and one polymer containing 70% phenyl. Two of the 50% phenyl polymers had one phenyl and one methyl group attached to each silicon atom. One of these also had 1% vinyl incorporated. The third 50% phenyl polymer was synthesized in such a way that one half of the silicon atoms had two phenyl groups attached while the rest contained dimethyl groups. The 70% phenyl polymer also had 4% vinyl incorporated. Due to the intrinsic thermal stability of these phenyl phases and the enhanced film stability achieved by crosslinking, the 70% phenyl phase could be utilized up to 400 °C. Using the methods described in this paper, highly efficient and thermally stable fused silica capillary columns coated with crosslinked methylphenylpolysiloxane stationary phases can be successfully prepared.

Pyrolysis gas chromatography of phenyl polymers and phenyl ether

Pyrolysis gas chromatography of phenyl polymers and phenyl ether