Polymer 2a Research Articles

A new solvent-free pathway for inducing quaternized lignin-derived high molecular weight polymer

In this work, kraft lignin (KL) was polymerized with vinylbenzyl chloride (VBC) in a molar ratio of 1.8:1 (KL: VBC) using sodium persulfate (Na2S2O8) as an initiator at pH 9–10 and temperature of 80–90 °C for 3 h to produce polymer kraft lignin-g-poly(4-vinylbenzyl chloride) KL-poly(VBC) 1. Then, the grafting reaction was conducted with two different imidazole-based monomers of different side-chain lengths (methyl and n-butyl), namely, 1-methylimidazole (MIM), 1-n-butylimidazole (BIM), which led to the formation of novel polymers, kraft lignin-g-poly(4-vinylbenzyl-1-methylimidazolium chloride) KL-poly(VBC-MIM) 2a and kraft lignin-g-poly(4-vinylbenzyl-1-n-butyl imidazolium chloride) KL-poly(VBC-BIM) 2b. The polymer 2a generated a larger molecular weight polymer with a higher charge density and solubility than polymer 2b since the n-butyl group would cause steric hindrance and weaker monomer to react with intermediate polymer 1 in the second stage. The contact angle analysis confirmed more hydrophilicity of polymer 2a, and elemental analysis confirmed the more successful polymerization of polymer 2a. Applying the generated polymers as flocculants for a kaolin suspension confirmed that polymer 2a had similar performance with commercial cationic polyacrylamide (CPAM) flocculants, even though polymer 2a had a smaller molecular weight. This polymerization offers a promising pathway for generating cationic polymers with excellent performance as a flocculant for suspensions.

Synthesis and Characterization of Thiol-Functionalized Polynorbornene Dicarboximides for Heavy Metal Adsorption from Aqueous Solution.

The contamination of water resources with heavy metals is a very serious concern that demands prompt and effective attention due to the serious health risks caused by these contaminants. The synthesis and ring-opening metathesis polymerization (ROMP) of norbornene dicarboximides bearing thiol pendant groups, specifically, N-4-thiophenyl-exo-norbornene-5,6-dicarboximide (1a), N-4-(methylthio)phenyl-exo-norbornene-5,6-dicarboximide (1b) and N-4-(trifluoromethylthio)phenyl-exo-norbornene-5,6-dicarboximide (1c), as well as their assessment for the removal of heavy metals from aqueous systems, is addressed in this work. The polymers were characterized by NMR, SEM and TGA, among others. Single and multicomponent aqueous solutions of Pb2+, Cd2+ and Ni2+ were employed to perform both kinetic and isothermal adsorption studies taking into account several experimental parameters, for instance, the initial metal concentration, the contact time and the mass of the polymer. In general, the adsorption kinetic data fit the pseudo-second-order model more efficiently, while the adsorption isotherms fit the Freundlich and Langmuir models. The maximum metal uptakes were 53.7 mg/g for Pb2+, 43.8 mg/g for Cd2+ and 29.1 mg/g for Ni2+ in the SH-bearing polymer 2a, 46.4 mg/g for Pb2+, 32.9 mg/g for Cd2+ and 27.1 mg/g for Ni2+ in the SCH3-bearing polymer 2b and 40.3 mg/g for Pb2+, 35.9 mg/g for Cd2+ and 27.8 mg/g for Ni2+ in the SCF3-bearing polymer 2c, correspondingly. The better performance of polymer 2a for the metal uptake was ascribed to the lower steric hindrance and higher hydrophilicity imparted by –SH groups to the polymer. The results show that these thiol-functionalized polymers are effective adsorbents of heavy metal ions from aqueous media.

A novel antimicrobial polymer efficiently treats multidrug-resistant MRSA-induced bloodstream infection.

The present study aimed to ascertain if polymer 2a, a novel synthesized antimicrobial polyionene, could treat methicillin-resistant Staphylococcus aureus (MRSA)-induced bloodstream infection. The minimum inhibitory concentration (MIC) of polymer 2a against MRSA was detected. A time-kill assay was employed to determine the killing kinetic of polymer 2a. Potential antimicrobial mechanisms of polymer 2a, including membrane disruption and programmed cell death (PCD), were explored. A resistance development assay was introduced to determine the propensity of polymer 2a toward resistance against MRSA. A mouse model of MRSA bacteremia was established to assess in vivo efficacy of polymer 2a. Furthermore, in vivo toxicity of polymer 2a was also evaluated through injection by tail vein. Polymer 2a exhibited more superior antimicrobial activity and faster killing kinetic than the control antibiotics against clinically isolated MRSA strains. Polymer 2a resulted in an obvious leakage of cellular components (concentration more than 1× MIC). mRNA expression of PCD pathway-related gene (recA) was significantly up-regulated in the presence of polymer 2a with low concentration (concentration less than 1× MIC). Repeated use of polymer 2a did not lead to drug resistance. In a MRSA-induced bloodstream infection mouse model, polymer 2a displayed superior therapeutic efficacy with negligible systemic toxicity. Moreover, polymer 2a treatment by tail vein could evidently reduce MRSA counts in blood and major organs and markedly improve living conditions. In conclusion, all these findings presented in this work convincingly suggested that polymer 2a may be a promising therapeutic alternative for treating MRSA-induced infections, especially bloodstream infection.

Synthesis of Fluorinated Polymers and Evaluation of Wettability.

Two kinds of fluorinated polymers were synthesized: an acrylate polymer having a fluorinated triethylene glycol as a pendant group (2a) and a fluoroalkyl acrylate polymer (2b). The contact angle of these fluorinated polymers against water, non-fluorinated alcohols and fluorinated alcohols were evaluated. As compared with the fluoroalkyl polymer (2b), fluoroethylene glycol polymer (2a) showed smaller contact angle against water and non-fluorinated alcohols. This supports the proposition that changing the alkyl chain into the ethylene glycol-type chain gave some interaction between etheric oxygen and water or non-fluorinated alcohols. In addition, fluoroalkyl acrylate polymer (2b) showed remarkably low values of critical surface tension.

Anionic polymerisation of phosphaalkenes bearing polyaromatic chromophores: phosphine polymers showing “turn-on” emission selectively with peroxide

Three new phosphaalkenes bearing C-aryl chromophores, MesPCPh(Ar) (1a: Ar = 1-naphthyl, 1b: 9-phenanthryl, 1c: 5-dibenzosuberenyl; Mes = 2,4,6-trimethylphenyl), are reported. Each phosphaalkene was characterised by multinuclear NMR spectroscopy (1H, 13C, 31P), X-ray crystallography, mass spectrometry, UV/Visible spectroscopy and elemental microanalysis (1b and 1c). Monomers 1a and 1b were successfully polymerised using anionic methods of initiation (n-BuLi: 5 and 1.5 mol%, respectively) to afford poly(methylenephosphine)s (PMPs: 2a: Mn = 15 100 Da, PDI = 1.14; 2b: Mn = 17 500 Da; PDI = 1.39). Detailed NMR spectroscopic analysis of polymer 2a revealed that its microstructure is primarily composed of [P(CHPhNaph)–(4,6-Me2C6H2)–2-CH2]n units rather than the expected [P(Mes)–CPh2]n. Functional polymer 2a was oxidised to the phosphine oxide 2a·O or phosphine sulfide 2a·S, and coordinated to borane to afford 2a·BH3 or gold(I) to afford 2a·AuCl. Significantly, 2a shows “turn-on” emission properties selectively as its oxide 2a·O (λex = 286 nm; λem = 342 nm) which is prepared by treatment with hydrogen peroxide.

Synthesis, gas permeability, and metal-induced gelation of poly(disubstituted acetylene)s having p,m-dimethoxyphenyl and p,m-dihydroxyphenyl groups

Diphenylacetylene having a trimethylsilyl group and two methoxy groups [p-(CH3)3SiC6H4CCC6H4-m,p-(OCH3)2 (1a)] polymerized with TaCl5/n-Bu4Sn catalyst to provide a high-molecular-weight polymer (2a). In contrast, monomers without trimethylsilyl group (1b) and having two t-butyldimethylsiloxy groups (1c) hardly polymerized because of poor solubility of the produced polymer 2b and steric hindrance of 1c. Polymer 3a with high molecular weight was obtained by desilylation of 2a using CF3COOH. Membranes having p,m-dihydroxyphenyl groups to certain degrees (4a: 40%; 4b 90%) were synthesized by cleavage of methoxy groups in the membrane of 3a using AlCl3. Membrane 4a showed high CO2 permselectivity, while membrane 5a was too brittle. Polymers 2a and 3a totally dissolved in CHCl3 and THF, and their solutions turned into gels upon addition of metal chlorides such as TaCl5, AlCl3, etc. The gels returned to solutions by adding a small amount of methanol. This indicates that 2a and 3a form non-covalent intermolecular bonds through metal–ligand interaction.

New Hofmann-like spin crossover compound with 3,5-lutidine

A new type III of 3,5-lutidine spin crossover coordination compound with formula Fe(3,5-lutidine)2Ni(CN)4·2[(H2O)(3,5-lutidine)] 2c has been obtained. The ratio of the high spin state (HS) iron (II) changing to the low spin state (LS) iron (II) in 2c is higher than that of type I and type II 3,5-lutidine coordination polymer 2a and 2b previously reported. 57Fe Mossbauer spectra of 2c show two different doublets which correspond to HS1 (inner doublet lines) and HS2 (outer doublet lines). The intensity of the HS1 doublet decreases on cooling to 80 K while the intensity of another component, the LS singlet, increases. The 90 % of the HS1 doublet change to the LS singlet is probably due to suitable environments of octahedral iron (II) ions coordinated by four nitrogen atoms of cyano groups and two nitrogen atoms of 3,5-lutidine ligands. We also prepared the Hofmann-like 3,5-dichloropyridine coordination compound Fe(3,5-dichloropyridine)2Ni(CN)4 ·2[(3,5-dichloropyridine)(H2O)] 2d to compare it with 2c. 57Fe Mossbauer spectra of 2d show that 2d is not a spin crossover coordination compound.

Thermosensitive nanosized micelles from cholesteryl-modified hydroxypropyl cellulose as a novel carrier of hydrophobic drugs

The thermosensitive micelles based on the two series of cholesteryl-modified hydroxypropyl cellulose (series 1 and 2, respectively) were used as a promising drug carrier. The polymers 1a and 2a with side chain substitution degrees DChol = 0.7 and 2.1 mol% were selected for micelle preparation, respectively. Polymeric micelles were prepared by the co-solvent evaporation method. The aqueous self-assembly of the polymers was studied using fluorescence analysis and transmission electron microscopy (TEM). The critical micelle concentrations (CMCs) values of the various DChol of polymers were evaluated in the range of ca. 0.13–0.29 g/L which decreased with the increase of DChol in both series. Furthermore, the CMC values displayed a downtrend profile, with increasing the temperature. The polymer 1a with less DChol had lower CMC than that of polymer 2a. By using the naproxen as a hydrophobic model drug, the drug-loaded micelles were prepared. The TEM image of naproxen-loaded micelles of polymer 1a with 40 % drug-loading efficiency and 8 % loading capacity showed that micelles were regularly spherical in shape with a mean diameter of 70 nm. The unmodified HPC exhibited a lower critical solution temperature (LCST) of more than 41 °C in water, while polymeric micelles in aqueous solution presented an LCST of 38.7 °C. A drug release study was performed by dialysis method in phosphate-buffered solution at 25, 37 and 40 °C, respectively. The release kinetics of naproxen from the polymeric micelles revealed a thermosensitivity, since its release rate was higher at 40 °C than at 25 °C.

STUDY ON THE ADSORPTION PROPERTIES OF NOVEL CALIX[6]ARENE POLYMERS FOR HEAVY METAL CATIONS

A research has been conducted to investigate the capability of a series of novel calix[6]arenes-based polymers: poly-monoallyloxycalix[6]arene (2a), poly-monoallyloxypenta-estercalix[6]arene (2b) and poly-monoallyloxypenta-acidcalix[6]arene (2c) for trapping of heavy metal cations such as Cd(II), Cu(II) and Cr(III). The existence of active hydroxy group (-OH) and with a tunnel-like structure of the polymers, caused the polymers can be used as adsorbents for heavy metals. The adsorption process was carried out in batch method in the variation of acidity (pH), contact time and initial concentration of metal ions. The results showed that the amount of adsorbed metal increased with the increasing of the pH of metal solution. For these three polymers, the amount of metal ions Cd(II), Cu(II) and Cr(III) adsorbed was optimum at pH 7, 6 and 5 respectively. The optimum contact time for Cd(II) and Cu(II) was 120 min, while that for Cr(III) was 60 min. Study of the adsorption kinetics showed that the adsorption of Cd(II), Cu(II) and Cr(III) using polymer 2a followed kinetics model of Ho. For adsorbent 2b and 2c, the adsorption kinetics of Cd(II) and Cr(III) also followed kinetics model of Ho while for the Cu(II) followed Lagergren kinetic models. Isothermal studies showed that the adsorption of metal ions on all adsorbents tend to follow the Langmuir isotherm. The adsorption energies of the three adsorbents were higher than 23 kJ/mole and polymer 2c has the largest adsorption capacity for Cr(III).

Synthesis of poly(p-phenyleneethynylene)s bearing oligo-ethylene glycols and their gas permeation properties

1,4-Diiodobenzenes bearing oligo-ethylene glycols [IRC6H2IR, R = OCH2CH2OCH3 (1a), O(CH2CH2O)2CH3 (1b), O(CH2CH2O)3CH3 (1c)] were polymerized with 1,4-diethynylbenzene in the presence of Pd/Cu catalyst to afford poly(p-phenyleneethynylene)s bearing oligo-ethylene glycols (2a–c), respectively. Polymer 2a was insoluble in any solvents, but the other polymers (2b, 2c) were soluble in CHCl3. The weight-average molecular weights of 2b and 2c were 5.4 × 104 and 9.6 × 104, respectively, and they gave free-standing membranes by solution-casting method. The densities of membranes of 2b and 2c were 1.26 and 1.22 g/cm3, respectively, and their carbon dioxide permeability coefficients were 12.9 and 13.5 barrers, respectively. The CO2/N2 separation factor of membrane of 2b was as large as 33.7. Membrane of 3b, which contains triethylene glycols, exhibited higher CO2 permselectivity, and the CO2/N2 separation factor was 50.0.

Synthesis and gas permeability of poly(p-phenyleneethynylene)s having bulky alkoxy or alkyl groups

Dipropynylbenzene with branched alkoxy and alkyl groups [CH3C≡CRC6H2RC≡CCH3, R = 2-methylpropoxy (1a), 3-methylbutoxy (1b), 4-methylpentoxy (1c), cyclohexylmethoxy (1d), 2-ethylhexoxy (1e), 2-octoxy (1f), 2-ethylhexyl (1g), and 2-octyl (1h)] were polymerized with Mo(CO)6 in the presence of 4-(trifluoromethyl)phenyl to afford poly(2,5-di(alkoxy or alkyl)-p-phenyleneethynylene)s (2a–h). Polymer 2a was insoluble in any solvents, but the other polymers (2b–h) were soluble in common organic solvents. The polymers with relatively long side chains (2e–h) had high molecular weight over 1.6 × 104 and gave free-standing membranes by solution-casting method. The densities of membranes of 2e–h were 0.914–0.998, and their fractional-free volume values were relatively large (0.094–0.158). The oxygen permeability coefficients of membranes of 2e–h were 18.4, 12.7, 4.85, and 19.3 barrers, respectively. It was found that poly(p-phenyleneethynylene) with 2-octyl side groups, which have the branch at the nearest position from main chain, exhibited the highest gas permeability.

Synthesis and Heat Resistance of Arylenedioxy-organosilanylene Polymers with Adamantane Units

Arylenedioxy-organosilanylene polymers with adamantane units in the backbone were prepared by Rh-catalyzed dehydrocoupling of bis(4-hydroxyphenyl)adamantanes with organohydrosilanes, and their heat resistance was evaluated by thermogravimetric analysis in nitrogen. Among these polymers, the highest Td10 (10% weight loss temperature) of 547 °C was achieved for polymer 2a prepared from 1,3-bis(4-hydroxyphenyl)adamantane and phenylsilane. Polymer 2a exhibited good heat resistance even in air with Td10 = 387 °C, and standing of the polymer at 150 °C for 8 h resulted in no evident weight loss

Synthesis and properties of new novolacs based on heteroatom‐bridged phenol derivatives

AbstractWe describe the synthesis and properties of new novolacs prepared by addition‐condensation of heteroatom‐bridged phenol derivatives and formaldehyde. The trifluoroacetic acid‐catalyzed polymerization of equimolar amounts of bis(4‐methoxyphenyl) ether (1a) and formaldehyde proceeded homogeneously to afford the polymer (2a) in 49% yield (Mn 2600, Mw/Mn 1.8). From the FTIR, 1H‐NMR, and 13C‐NMR spectra of 2a, it was evident that the polymer had methylene moieties‐bridged repeating units in the polymer backbone. A higher molecular weight novolac (2a′) (yield 99%, Mn 16,600, Mw/Mn 12.9) could be prepared by using an excess of formaldehyde. Bis(4‐methoxyphenyl) sulfone novolac (2b) (Mn 1300, Mw/Mn 1.2) and bis(4‐methoxyphenyl) sulfide novolac (2d) (Mn 1200, Mw/Mn 1.9) were also prepared. However, the polymerization of bis(4‐hydroxyphenyl) sulfone (1c) did not proceed, even when it was attempted under various reaction conditions. From TGA, the temperatures at 10% loss in weight (T10) for 2a, 2a′, and 2b were found to be 413, 430 and 393°C, respectively. These results suggested that heteroatom‐bridged novolacs based on phenol derivatives have good thermal stability than other organosoluble polymers; moreover, these novolacs could be expected to function as processable materials, polymer blends for engineering plastics, etc. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

A hybrid‐type, chiral π‐conjugated polymer wrapped with polyhedral oligomeric silsesquioxanes

AbstractA novel hybrid‐type chiral binaphthyl‐based polyarylene derivative with polyhedral oligomeric silsesquioxanes (POSS) units 2a was prepared by Suzuki–Miyaura coupling polymerization from a chiral (R)‐6,6′‐dibromo‐2,2′‐diPOSS‐substituted 1,1′‐binaphthyl derivative 1a and p‐biphenylene diboronic acid. As a reference, a binaphthyl‐based polyarylene derivative without POSS unit 2b was also prepared. The obtained polymers were studied with thermogravimetric analysis, optical rotations, circular dichroism (CD), ultraviolet‐visible, and photoluminescence (PL) spectra. Gel permeation chromatography measurements of 2a and 2b showed that their number‐average molecular weights were 13,300 and 16,500, respectively. The thermal stability of POSS‐modified polymer 2a (temperature of 10% weight loss; T10 = 380 °C) was extremely high compared with that of polymer without POSS unit 2b (T10 = 335 °C) due to the siliceous bulky POSS segments on the side chains. The specific optical rotation [α]D was −66.7° (c 0.06, CHCl3) for 2a and −62.3° (c 0.06, CHCl3) for 2b. The CD spectra showed that these two polymers had very similar and strong Cotton effects. Film polymer 2a showed almost the same PL spectrum as that in dilute CHCl3 solution, indicating that bulky POSS units strongly suppressed intermolecular aggregation of the π‐conjugated polymer backbone. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6035–6040, 2008

Synthesis and Properties of Fluorine-Containing Poly(arylenemethylene)s as New Heat Resistant Denatured Phenolic Resins

We report the synthesis of fluorine-containing poly(arylenemethylene)s as a new heat-resistant denatured phenolic resin by addition-condensation or Friedel-Crafts polymerization. In the case of polymerization of 2,2-bis(4-methoxyphenyl)hexafluoropropane (1a) with an equimolar amount of formaldehyde, the polymerization proceeded homogeneously to give the polymer 2a (Mn 8,200, Mw/Mn 2.1) in 71% yield. The FT-IR, 1H NMR and 13C NMR spectra of 2a revealed that it had arylene-methylene units on the polymer backbone. The polymerizations of 3-(trifluoromethoxy)benzyl bromide (1b) or 4-(trifluoromethoxy)benzyl bromide (1c) via the Friedel-Crafts polymerization using aluminum chloride as a catalyst produced the polymer 2b and 2c in 38% and 16% yield, respectively. From the TGA, the temperatures at 10% loss in weight (T10) of 2a and 2c were found to be 425 and 298 °C, respectively. As compared to the non-fluorinated poly(arylenemethylene) derived from 2,2-bis(4-methoxyphenyl)propane-formaldehyde polymer (2d) (T10=397 °C), 2a showed high thermostability in terms of the temperature of T10. The results indicated that the thermal stability of poly(arylenemethylene)s was enhanced by the introduction of fluorine moieties in the polymer.

Synthesis of Highly Water-Soluble Fluorescent Conjugated Glycopoly(p-phenylene)s for Lectin and Escherichia coli

Two facile, convenient, and versatile synthetic approaches are used to covalently attach carbohydrate residues to conjugated poly(p-phenylene)s (PPPs) for highly water-soluble PPPs bearing alpha-mannopyranosyl and beta-glucopyranosyl pendants (polymers A and B), which highly fluoresce in phosphate buffer (pH 7.0). The post-polymerization functionalization approach is to treat bromo-bearing PPP (polymer 1) with 1-thiolethyl-alpha-D-mannose tetraacetate or 1-thiol-beta-D-glucose tetraacetate in THF solution in the presence of K(2)CO(3) at room temperature through formation of thioether bridges, affording polymer 2a or 2b. The prepolymerization functionalization approach is to polymerize a well-defined sugar-carrying monomer, affording polymer 2a. Polymers 2a and 2b were deacetylated under Zemplén conditions in methanol and methylene chloride containing sodium methoxide, affording polymers A and B, respectively. The multivalent display of carbohydrates on the fluorescent conjugated glycopolymer overcomes the characteristic low binding affinity of the individual carbohydrates to their receptor proteins. Titration of concanavalin A (Con A) to alpha-mannose-bearing polymer A resulted in significant fluorescent quenching of the polymer with Stern-Volmer quenching constant of 4.5 x 10(7). Incubation of polymer A with Escherichia coli (E. coli) lead to formation of fluorescently stained bacterial clusters. Beta-glucose-bearing polymer B displayed no response to Con A and E. coli.

Exo-Coordination-Based Supramolecular Silver(I) Complexes of S2O Macrocycles: Effect of Ligand Isomerism on the Structural Diversity

An isomeric series of S2O macrocycles incorporating a xylyl group at the ortho (L1), meta (L2), and para (L3) positions were employed to examine the influence of the ring rigidity on silver(I) coordination modes in resulting supramolecular complexes (1-3); L1 and L3 afforded sandwich (1; Ag:L1 = 1:2) and infinite 1-D (3) complexes, respectively; otherwise, L2 gave the 1-D polymer (2a), 2:3 club sandwich (2b), and unique 2:4 bridged dinuclear complex (2c) complexes, in which their topologies vary with the solvent used.

Chirality Induction in Cyclopolymerization XVI. Synthesis of Optically Active Poly(methyl acrylate-co-dimethyl fumarate) by Radical Cyclopolymerization of Asymmetrical Nonconjugated Diene Having Chiral Pentanediol

The molecular design and synthesis of asymmetric bifunctional monomers, 3-(S)-acryloyloxy-1-(S)-methyl-butyl methyl fumarate (1a) and 3-(R)-acryloyloxy-1-(R)-methyl-butyl methyl fumarate (1b), have been carried out in terms of a novel method of producing optically active polymers based on cyclopolymerization. The polymerization of 1 proceeded via the cyclopolymerization mechanism to yield the cyclopolymer 2 with the extent cyclization of 0.87–0.96 when the monomer concentration ([M]) in the feed was 0.3 mol L-1 or less. The number-average molecular weight (Mn) decreased with a decrease in the [M] from 8300 to 3300 for polymer 2a and from 4200 to 2400 for polymer 2b. The specific rotation ([α]43523, c 1.0, CHCl3) of the resulting polymers changed from +19.3° to +33.4° for 2a and from -26.2° to -34.9° for 2b. In order to confirm the chirality induction, the chiral pentanediyl moiety was removed from polymer 2 by saponification, and the hydrolyzed polymer was treated with diazomethane to give poly(methyl acrylate-co-dimethyl fumarate) (3). The Mn was 2200–2600 for 3a and 2300–5700 for 3b, and the template-free polymers showed an optical activity with a specific rotation that ranged from -1.4° to -9.3° for 3a and from +7.5° to +8.8° for 3b. The CD spectra of 3a showed a positive Cotton effect whereas 3b showed a negative Cotton effect which is the mirror image of 3a. The optical activity of polymer 3 should be attributed to the threo-erythro sequence of the methyl acrylate and dimethyl fumarate units.

Regio- and Stereoselective Cyclopolymerization of 1,2:5,6-Dianhydroallitol and 1,2:5,6-Dianhydrogalactitol Leading to a Novel Carbohydrate Polymer of (2→6)-1,5-Anhydro-dl-galactitol

The cyclopolymerizations of two meso dianhydrohexitols, 1,2:5,6-dianhydro-3,4-di-O-methylallitol (1) and -galactitol (3), were examined to form a polymer with six-membered ring repeating units. Distinct from the cases of 1,2:5,6-dianhydro-3,4-di-O-methyl-d-mannitol (5), -l-iditol (6), and -d-glucitol (7) in which the five-membered ring units were formed with high regio- and stereoselectivity, six-membered ring units were found in polymers 2b, 4a, and 4b obtained by the polymerizations of 1 and 3. The anionic polymerization of 1 with t-BuOK was highly regio- and stereoselective to form polymer 2a consisting of five-membered ring units, but that of 3 was different in the scission mode of the epoxy groups to form polymer 4a consisting essentially of six-membered ring units. The cationic polymerization of 1 with BF3·OEt2 produced polymer 2b having a structure consisting of the six-membered ring units as major constituents and five-membered ring units as minor ones. The structure of polymer 4b from the cationi...

Langmuir-Blodgett Films of Polybenzothiazole Prepared by Precursor Method

Abstract Polyamide with side chain carboxylic acid 1a, which was the precursor polymer for polybenzothiazole, was mixed to obtain the precursor salt polymer 2a with the three armed tertiary amine in a mixture of benzene and N,N-dimethylacetamide (1:1). The solution was spread onto the water surface to prepare the L film of 2a. The LB film of 2a, which was successfully obtained with the Y type deposition, was converted to the LB film of polybenzothiazole (PBT) 3a by heating at 280 °C with removal of the tertiary amine. The FTIR and UV-Vis absorption spectra, and the elemental analysis obtained by XPS proved the chemical structure of the PBT LB film. The measurement of SAXS indicated the thickness of the precursor LB films was 2.9 nm, where the results of the ellipsometry were 2.8 and 0.34 nm for the precursor and PBT LB films, respectively.