Structure and Properties of Phosphorous‐Containing Thermotropic Liquid‐Crystalline Aliphatic–Aromatic Copolyesters

A series of thermotropic liquid crystalline aliphatic–aromatic copolyesters derived from various ratios of dodecane‐1,12‐diol ( 1 ), terephthaloyl bis‐(4‐oxybenzoyl‐chloride) ( 2 ), and 2‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉 oxaphosphorin‐6‐yl)‐1,4‐naphthalene diol ( 3 ), has been synthesized. The chemical structures of the monomers and polymers have been confirmed by elemental analyses, and FT‐IR and ¹H NMR spectroscopy. The mesomorphic properties of polymers have been investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the content of the aliphatic unit on the phase behavior of the polymers has been examined. The polymers that contain >30 mol‐% aliphatic diol showed smectic phases while the polymers that contained <30 mol‐% aliphatic diol displayed nematic phases. The polymers revealed a reversible mesomorphic phase transition, wide mesophase temperature ranges, and high thermal stability. The degree of crystallinity increased upon increasing the content of aliphatic moieties. The char yield at high temperature increased by increasing the content of phosphorous‐containing bisphenol.

     

High Glass‐Transition Temperature Acrylate Polymers Derived from Biomasses,Syringaldehyde, and Vanillin

The contribution reports a unique type of lignin‐based (meth)acrylate polymers which are derived from syringaldehyde and vanillin and show high glass transition temperature (T_g). The four (meth)acrylate monomers undergo free radical polymerization and yield the corresponding polymers in high yield (>80 wt%). The obtained polymers display relatively higher thermostability. Especially, the polymers demonstrate remarkably high glass transition temperature (T_g), well exemplified by syringaldehyde‐derived polymers which show a T_g up to 180 °C. This type of polymers can be applied as novel high temperature‐resistant plastics and even heat‐resistant additives for other general polymers.

     

Macromolecular Crystal Engineering Based on Segmented Polymers: Influence of Heteroatoms on the Thermal Properties and Crystallization of m,n‐Polyurethanes Derived from Long‐Chain,Heteroatom‐Containing,Monodisperse α,ω‐Diols

Long‐chain heteroatom‐containing telechelic diols with 29–32 atoms in the backbone were synthesized by a one‐step, free‐radical telomerization of 10‐undecene‐1‐ol with commercially available α,ω‐dithiols. The oxygen and sulfur atoms caused a decrease in the melting point and enthalpy of the diols, compared to the corresponding purely aliphatic diols. The heteroatom‐containing α,ω‐diols HO? (CH₂)₁₁? S? (CH₂)₂? X? (CH₂)₂? S? (CH₂)₁₁? OH, where X = CH₂, O, or O? (CH₂)₂? O, were reacted in the melt with 1,6‐diisocyanatohexane O?C?N? (CH₂)₆? N?C?O, producing a series of polyurethanes containing an increasing amount of heteroatoms. Characterization by differential scanning calorimetry, infra‐red spectroscopy, thermogravimetric analysis, and wide angle x‐ray scattering of the m,n‐polyurethane series showed that, like the telechelic diols they were synthesized from, the heteroatoms caused a decrease in the melting point and enthalpy. However, they did not affect either the decomposition temperature or the crystal structure/packing.

Typical decomposition behavior of all the heteroatom‐containing m,6‐polyurethane.     

Thermal,Optical and Electrochemical Properties of Side‐Chain Azopyridine Polymers Complexed with Metalloporphyrins

Summary: New multifunctional supramolecular polymers were obtained by complexing a side‐chain azopyridine polymer with ZnTPP and CoTPP via axial coordination between the pyridyl group and the transition metals of the metalloporphyrins. Thermal, optical and electrochemical properties of the complexes in the solid state at various molar ratios of metal/pyridine were characterized by means of DSC, TGA, UV‐vis spectroscopy and CV. On one hand, the results show that linking ZnTPP or CoTPP to the azopyridine polymer results in significant changes of its properties, such as an increase in the glass transition temperature and the thermal stability of the polymer, and a decrease in the trans‐cis photoisomerization of azopyridine moieties. On the other hand, both ZnTPP and CoTPP complexed with the polymer exhibit changes in their redox behaviors.

Complexation via axial coordination between PAzPy and ZnTPP or CoTPP.     

Synthesis and Properties of New N‐Methylated Aliphatic‐Aromatic Polyamides Derived from N,N′‐Dimethylalkylenediamines and 4,4′‐Biphenyl‐dicarboxylic and 4,4″‐p‐Terphenyldicarboxylic Acids

Two new series of N‐methylated aliphatic‐aromatic polyamides were prepared by interfacial polycondensation of N,N ′‐dimethylalkylenediamines having 6–10 methylene units with 4,4′‐biphenyldicarbonyl and 4,4″‐p‐terphenyldicarbonyl chlorides. All of the N‐methylated polyamides were soluble in chlorinated hydrocarbon solvents, and the solubilities of the biphenyl‐based polyamides were higher than those of the terphenyl‐containing polymers. The biphenyl‐bearing polyamides with an even‐number of methylene units were crystalline and their odd‐numbered neighbors were amorphous, whereas all of the terphenyl‐containing polymers were crystalline. The melting temperatures of the terphenyl‐based polyamides (220–307°C) were higher than those of the biphenyl‐bearing polymers (180–207°C). Among these N‐methylated polyamides, the terphenyl‐containing polyamide having 7 methylene units showed enantiotropic liquid crystallinity.     

Synthesis and Photovoltaic Properties of Alternating Conjugated Polymers Derived from Indeno[1,2‐b]fluorene and Bithiophene or Thieno[3,2‐b]thiophene‐Cored Benzothiadiazole

Two narrow bandgap copolymers derived from 6,6′,12,12′‐tetraoctyl‐indeno[1,2‐b]fluorene and bithiophene or thieno[3,2‐b]thiophene‐cored benzothiadiazole are synthesized and characterized. The copolymers show broad absorption in the range 350–700 nm. The application of the copolymers as photovoltaic cells with configurations ITO/PEDOT:PSS/blend/Al and ITO/PEDOT:PSS/blend/interlayer/Al is investigated. A power conversion efficiency (PCE) of approximately 3.0% is achieved under an AM 1.5G solar simulator (80 mW cm^?2) for the cells with ITO/PEDOT:PSS/polymer:PC₇₁BM([6,6]‐phenyl‐C₇₁ butyric acid methyl ester) (1:4)/interlayer/Al.

     

Biobased Copolymers Composed of l‐Lactic Acid and Side‐Chain‐Substituted Lactic Acids: Synthesis,Properties, and Solid‐State Structure

Various biobased copolyesters composed of l ‐lactic acid (LLA) and side‐chain‐substituted lactic acids (SLAs) with high molecular weight and LLA‐rich composition are synthesized by direct solution polycondensation. Glycolic acid, 2‐hydroxyisobutyric acid, (S)‐2‐hydroxy‐3‐methylbutanoic acid (LVOH), and (S)‐2‐hydroxy‐4‐methylpentanoic acid (LLOH) are chosen as SLAs. Wide‐angle X‐ray diffraction (WAXD) and small‐angle X‐ray scattering (SAXS) reveal that the substituent size of the SLAs determines whether or not SLA units are included in crystallites of the LLA sequences. Unlike poly(l ‐lactic acid), tensile necking is seen in the copolymers with 2 mol% LVOH and with 6 mol% LLOH. Enzymatic degradation is accelerated with increasing SLA content. Especially for 6 mol% LLOH, the SLA introduction improves both the mechanical properties and the enzymatic degradability.

     

Copolymers from Methacrylic Acid and Trimethylsilyl Methacrylate ‐ Synthesis,Reactivity Ratios and Thermal Properties

Copolymers from methacrylic acid (1) and trimethylsilyl methacrylate (2) have been synthesized by free radical copolymerisation and by controlled desilylation of poly(trimethylsilyl methacrylate) (3). The reactivity ratios were r₁ = 2.75, r₂ = 0.004. Differential scanning calorimetry showed a linear correlation between the peak temperature of the endotherm for the formation of cyclic anhydrides and the content of methacrylic acid in the copolymer. Obviously, the acid catalyses this reaction. The copolymers as well as poly(trimethylsilyl methacrylate) have a ceiling temperature. Sequence distributions were calculated and used to predict glass transition temperatures for comparison to the experimental results. The microstructure of the copolymers obtained by the different synthetic routes is different as shown from T_g and from their solubility. Those from desilylation are random with “reactivity ratios” of 1, those from copolymerisation seem to have longer sequences of methacrylic acid leading to formation of intermolecular aggregates.

Dependence of DSC peak temperature of anhydride formation on methacrylic acid content.     

Polybenzimidazoles (PBIs) Derived from Non‐Coplanar Dibenzoic Acid Containing Imidazole (IDBA): Synthesis,Characterization and Properties

A novel non‐coplanar imidazole dibenzoic acid (IDBA) was successfully prepared, and its structure was carefully characterized by FT‐IR, NMR, MS and elemental analysis. Polybenzimidazoles (PBIs) derived from IDBA were synthesized by a conventional one‐step method in polyphosphoric acid (PPA). The obtained PBIs exhibited good organic solubility, excellent thermo‐stability and interesting optical properties. The initiation decomposition temperature for these PBIs ranged from 560–600 °C, and the 5% weight loss temperature (T₅) for all these PBIs was above 600 °C in N₂. No obvious glass transition for these PBIs was observed below 350 °C. These PBIs shows UV‐vis absorption maximum around 360–380 nm and strong photoluminescence emission (blue light) around 430–440 nm in solution, which is red‐shifted to 490–510 nm in the solid state.

     

Liquid–Liquid Extraction of 3FOx and 5FOx Polyoxetane Diols: Impact on Polyurethane Mechanical Properties,Surface Morphology,and Wetting Behavior

Laboratory prepared and commercial poly(2‐2,2,2‐trifluoroethoxy‐2‐methyl)oxetane, P[3FOx] and poly(2‐2,2,2‐pentafluoropropoxy‐2‐methyl)oxetane, P[5FOx] polyols contain varying amounts of cyclics and low molar mass (LMW) constituents as byproducts of ring opening polymerization. Guided by phase diagrams determined by cloud point measurements, P[3FOx] diol separation is achieved. The impact of purification is explored via the preparation of P[3FOx] and P[5FOx] polyurethanes from cyclic/LMW‐free diols. Mechanical properties are improved because of higher polyurethane molecular weights. AFM revealed complex rugosity that is correlated with dynamic contact angles free from effects of water contamination.     

Synthesis,Self‐Assembly,and Properties of Homoarm and Heteroarm Star‐Shaped Inorganic–Organic Hybrid Polymers with a POSS Core

Novel homoarm and heteroarm star‐shaped inorganic–organic hybrid polymers with a polyhedral oligomeric silsesquioxane (POSS) core are prepared via click chemistry of azide POSS [POSS‐(N₃)₈], alkynyl poly(L ‐lactide) (PLLA), and alkynyl poly(ethylene oxide) (PEO). The melting and crystallization behaviors of the polymers can be adjusted by altering the PLLA to PEO ratio. The hybrid polymers reveal unique crystalline morphology due to the influence of the star‐shaped structure and the mutual influence of PLLA and PEO. The hybrid polymers show different thermostabilities, owing to the different compositions of the polymers. The hydrophilicity can be adjusted by alternating the composition of the PLLA and PEO segments. In addition, the sizes of the polymer micelles change with the change of the ratio of PLLA and PEO arms in the hybrid polymers.

     

Dextran‐Based Polycations: Thermodynamic Interaction with Water as Compared With Unsubstituted Dextran, 1 – Volumetric Properties and Light Scattering

Dextran and random dextran‐based copolymers containing different molar fractions f of charged units are studied in aqueous solution and in the pure state. The specific volumes of the solutions decrease linearly with increasing weight fraction of the polymer. Extrapolation to the pure state yields information on the hypothetical liquid polymers, exhibiting a pronounced minimum at f ≈ 0.1. A similar dependence is also observed for the pure solid polymers; however, the specific volumes at low f are considerably larger and at high f are slightly smaller. These differences are discussed in terms of the non‐equilibrium structures formed during sample preparation. The thermal expansivities of the solutions pass through a maximum at f ≈ 0.1. Light scattering shows that the thermodynamic quality of water has a minimum at f ≈ 0.1.

     

Synthesis of Alternating Low‐Bandgap Conjugated Polymers Based on Dithieno[2,3‐d:2′,3′‐d′]naphtho[1,2‐b:3,4‐b′]dithiophene and Enhancement of Photovoltaic Properties with Solvent Additives

Two alternating low‐bandgap conjugated polymers with 10,11‐di(3,7‐dimethyloctyloxy)di‐thieno[2,3‐d:2′,3′‐d′]naphtho[1,2‐b:3,4‐b′]dithiophene (NDT) as electron‐donor moieties and N,N′‐di(2‐hexyldecyl)isoindigo (ID) or bis(thieno‐2‐yl)‐N,N′‐bis(2‐hexyldecyl)‐1,4‐dioxo‐pyrrolo[3,4‐c]pyrrole (DPP) as electron‐acceptor moieties, respectively named as PNDT‐ID and PNDT‐DPP, are firstly synthesized and characterized. The polymers exhibit appropriate energy levels, good solution processabilities and broad light absorption properties; the power conversion efficiencies (PCEs) of 0.16%–0.19% for the photovoltaic solar cells (PVCs) from the blend films of the polymers and [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) are very low. The performances of the PVCs from the polymers are remarkably increased when a very small amount of 1,8‐diiodooctance (DIO) or diphenyl sulfide (DPS) is used as solvent additives, and the maximal PCEs of 3.79% and 5.01% are respectively achieved in the PVCs from the blend films of PNDT‐ID/PC₇₁BM (W:W, 1:1.5) and PNDT‐DPP/PC₇₁BM (W:W, 1:1.5), with DPS as solvent additives under 100 mW cm^?2 illumination (AM 1.5G).

     

Radical Copolymerization of Vinylidene Fluoride with 8‐Bromo‐1H,1H,2H‐perfluorooct‐1‐ene: Microstructure,Crosslinking and Thermal Properties

An original synthesis of 8‐bromo‐1H,1H,2H‐perfluorooct‐1‐ene (BDFO) and its radical copolymerization with vinylidene fluoride (VDF), initiated by 2,5‐bis(tert‐butylperoxy)‐2,5‐dimethylhexane at 134 °C, are presented. The fluorinated bromoalkene was obtained by dehydrobromination of 1,8‐dibromo‐1H,1H,2H,2H‐perfluorooctane in a satisfactory yield. Although BDFO did not homopolymerize under radical initiation, it did copolymerize with VDF. The compositions of the resulting random type copolymers were calculated by means of ¹⁹F NMR spectroscopy and allowed the quantification of the respective amounts of both comonomers in the copolymers, showing good incorporation of the brominated monomer. Nevertheless, obtaining PVDF copolymers containing a high molar percentage of BDFO in good yields was difficult to achieve from initial molar ratios of BDFO higher than 9.2 mol‐%. Radical terpolymerization of VDF, BDFO and hexafluoropropene (HFP) was also successfully achieved. BDFO contents in these co‐ or terpolymers ranged from 3.6 to 12.2 mol‐%. The bromoalkene acted as a cure site monomer and the resulting poly(VDF‐co‐BDFO) copolymers were crosslinked via the bromine atom in the presence of a triallyl isocyanurate/peroxide system. The materials obtained led to more thermally stable copolymers than the uncured ones and their thermostabilities were compared to those of commercially available poly(VDF‐co‐HFP) copolymers crosslinked using diamines.

     

New Hyper‐Crosslinked Partly Conjugated Networks with Tunable Composition by Spontaneous Polymerization of Ethynylpyridines with Bis(bromomethyl)arenes: Synthesis,Spectral Properties,and Activity in CO2 Capture

Spontaneous catalyst‐free polymerizations of 4‐ethynylpyridine (4EPy) and 2‐ethynylpyridine with bifunctional quaternizing agents (QAs) of bis(bromomethyl)arenes provide highly crosslinked polymer networks in high yields. ¹³C cross‐polarization magic‐angle spinning (CP/MAS) NMR, Fourier transform IR (FTIR) and diffuse reflectance vis spectroscopy confirm that these networks consist of polyacetylene main chains substituted with pyridyl and pyridiniumyl groups, the latter interconnected with –CH₂(arylene)CH₂– linkers. Variation of the 4EPy/QA ratio in the polymerization feed results in networks with different extents of crosslinking and pyridyl/pyridin­iumyl ratio (N/N⁺ from 0 to 1.32). Networks exhibit photolumi­nescence and are also moderately active in CO₂ capture (the highest uptake is 16.4 cm³ (STP) g^?1 at 293 K and an equilibrium CO₂ pressure of 750 Torr).

     

Sleep timing is associated with diet and physical activity levels in 9–11‐year‐old children from Dunedin,New Zealand: the PEDALS study

It is well documented that short sleep duration is associated with excess body weight and poor food intake in children. It has been suggested that sleep timing behaviour may also be an important predictor of weight and other related behaviours, independent of sleep duration; however, there is a lack of research investigating these relationships. The present study investigated sleep timing in association with diet and physical activity levels in 439 children aged 9–11 years old from New Zealand. Sleep and physical activity data were collected using accelerometry, and food choice using a short food‐frequency questionnaire. Participants were classified into one of four sleep timing behaviour categories using the median split for sleep‐onset and ‐offset times. Differences between sleep timing groups for weekly consumption frequency of selected food groups, dietary pattern scores and minutes of moderate‐to‐vigorous physical activity were examined. Children in the late sleep/late wake category had a lower ‘Fruit & Vegetables’ pattern score [mean difference (95% CI): ?0.3 (?0.5, ?0.1)], a lower consumption frequency of fruit and vegetables [mean weekly difference (95% CI): ?2.9 (?4.9, ?0.9)] and a higher consumption frequency of sweetened beverages [mean weekly difference (95% CI): 1.8 (0.2, 3.3)] compared with those in the early sleep/early wake category. Additionally, children in the late sleep/late wake category accumulated fewer minutes of moderate‐to‐vigorous physical activity per day compared with those in the early sleep/early wake category [mean difference (95% CI): ?9.4 (?15.3, ?3.5)]. These findings indicate that sleep timing, even after controlling for sleep duration, was associated with both food consumption and physical activity.