Thermal transitions of ethylene-vinyl chloride copolymers

Differential scanning calorimetry (d.s.c.) measurements were performed on a series of ethylene-vinyl chloride (E–V) copolymers for the purpose of studying the dependence of their thermal transitions upon their microstructure. The method of preparation, via reductive dechlorination of poly(vinyl chloride) with tributyltin hydride, resulted in a series of E–V copolymers differing only in comonomer content, sequence distribution and stereoregularity of adjacent V units. Chain length distribution and branching frequencies were identical for each member of the series.Extrapolation of glass transition temperatures, T_g, measured for our E–V copolymers to pure polyethylene (PE) predicted a T_g = ?85°C ± 10°C for amorphous PE. E–V copolymers with greater than 60 mol% E units exhibited melting endotherms characterized by melting temperatures from 20°C to 128°C and degrees of crystallinity from 12 to 63%. Observed melting temperatures were plotted against the composition of the E–V copolymers and compared to Flory's equation for melting point depression of random copolymers containing one crystallizable and one non-crystallizable monomer unit. The melting point depressions observed for our E–V copolymers were in agreement with Flory's theory, if the CH₂CH₂ moiety is considered to be the crystallizable unit and theCHmoiety is assumed to prevent the CH₂CH₂ units attached on either side from being incorporated into the crystal. This implies that among all possible comonomer triad sequences only the EEE triad may crystallize. Therefore only those E–V copolymers with average lengths of consecutive E units greater than 2 exhibit crystallinity.     

Adiabatic compressibility of polyelectrolytes: Effect of solvents on copolymers of vinyl pyrrolidone with acrylic acid and N-dimethylaminoethyl methacrylate

The results of adiabatic compressibility measurements for two copolymers, acrylic acid-vinyl pyrrolidone (AA—VP) and N-dimethylaminoethyl methacrylate-vinyl pyrrolidone (DAM—VP), in three different solvents, namely, water, methanol, and dioxane, have been described. The molecular weight of copolymers was determined by the light scattering method and the IR and NMR spectra of the polymers and copolymers were examined to establish that the alternating acrylic acid–vinyl pyrrolidone and N-dimethylaminoethyl methacrylate–vinyl pyrrolidone structure exists in the copolymers. The AA—VP copolymer behaves as a slightly weaker acid than the homopolymer of acrylic acid, while DAM—VP copolymer is very feebly basic and has the same strength as that of the homopolymer of N-dimethylaminoethyl methacrylate. The reduced viscosity for the two copolymers in aqueous solution is very low (～0.08 dL/g for AA—VP copolymer). In methanol solution AA—VP and DAM—VP copolymers show a decrease of øK^°₂ and øV^°₂ by 61.6 × 10^?4 cc/bar/mol and 8.0 cc/mol, and 191.0 × 10^?4 cc/bar/mol and 20.0 cc/mol, respectively, over that of the values of aqueous solution. The void space around the solute is smaller in methanol than in water, and accordingly this decrease has been attributed to geometric effect. Only one copolymer, DAM—VP is soluble in dioxane, and the values are seen to have increased in this solution by 71.0 × 10^?4 cc/bar/mol and 18.7 cc/mol, respectively, compared to the values obtained from aqueous solution. The experimentally determined øK^°₂ and øV^°₂ for AA—VP and DAM—VP copolymer are 0.6 × 10^?4 cc/bar/mol, and 102.4 cc/mol and ?61.0 × 10^?4 cc/bar/mol, 94.4 cc/mol, respectively, in aqueous solution, and ?12.0 × 10^?4 cc/bar/mol, 211.0 cc/mol and ?203.0 × 10^?4 cc/bar/mol, 191.0 cc/mol, respectively, in methanol solution. In dioxane solution the values for DAM—VP copolymer are 59.0 × 10^?4 cc/bar/mol and 229.7 cc/mol, respectively. These experimentally determined values for AA—VP copolymer show an increase by 0.04 × 10^?4 cc/bar/mol, 4.4 cc/mol and 28.3 × 10^?4 cc/bar/mol, 8.0 cc/mol in aqueous and methanol solution, respectively, compared to calculated values determined on the basis of no interaction between acid and the pyrrolidone group. In contrast, the DAM—VP copolymer shows a decrease of 27.6 × 10^?4 cc/bar/mol and 10.3 cc/mol, 149.3 × 10^?4 cc/bar/mol and 20.2 cc/mol, and 23.0 × 10^?4 cc/bar/mol and 4.1 cc/mol in aqueous, methanol, and dioxane solutions, respectively. In aqueous solution these differences between calculated and observed values have been attributed to a change of water structure around the copolymer chain. A similar effect is responsible for the difference of the values in the methanol solution also. In the dioxane solution the difference is rather small, and the solvent structure has probably not altered much due to the presence of the DAM unit in the chain.     

Polyethylene‐block‐poly(ε‐caprolactone) diblock copolymers: synthesis and compatibility

A strategy is introduced for the synthesis of polyethylene‐block‐poly(ε‐caprolactone) block copolymers by a combination of coordination polymerization and ring‐opening polymerization. First, end‐hydroxylated polyethylene (PE‐OH) was prepared with a one‐step process through ethylene/3‐buten‐1‐ol copolymerization catalyzed by a vanadium(III) complex bearing a bidentate [N,O] ligand ([PhN?C(CH₃)CHC(Ph)O]VCl₂(THF)₂). The PE‐OH was then used as macroinitiator for ring‐opening polymerization of ε‐caprolactone, leading to the desired nonpolar/polar diblock copolymers. The block structure was confirmed by spectral analysis using ¹H NMR, gel permeation chromatography and differential scanning calorimetry. The unusual topologies of the model copolymers will establish a fundamental understanding for structure–property correlations, e.g. compatibilization, of polymer blends and surface and interface modification of other polymers. © 2014 Society of Chemical Industry     

New fluorinated polysiloxanes containing an ester function in the spacer—II. Surface tension studies

The surface tensions of fluorinated polysiloxanes prepared by hydrosilylation of unsaturated perfluoroalkyl esters derived from undecylenic acid [CH₂?CH? (CH₂)₈? COO? CH₂? CH₂? R_F, with R_F = C₆F₁₃, C₈F₁₇, and C₈F₁₇? (CH₂)₁₀COO? CH₂? CH₂? CH?CH₂] by methylhydrodimethylsiloxane copolymers of various Si? H contents have been measured. The critical surface tensions, γ_c, and the solid surface tensions, γ^D_s, were deduced from n-alkane and water contact angle data. They decrease as the perfluoroalkyl graft content of the copolymers increases. Some of them, which are in the range of the lowest surface tension fluoro polymers known, are observed when the fluorinated segments are self-organized at the interface, i.e. when the polymers are mesomorphous or crystalline at room temperature.     

Miscibility and phase behavior in blends containing random copolymers of poly(ether ether ketone) and phenolphthalein poly(ether ether ketone)

The miscibility and phase behavior of polysulfone (PSF) and poly(hydroxyether of bisphenol A) (phenoxy) with a series of copoly (ether ether ketone) (COPEEK), a random copolymer of poly(ether ether ketone) (PEEK), and phenolphthalein poly(ether ether ketone) (PEK-C) was studied using differential scanning calorimetry. A COPEEK copolymer containing 6 mol % ether ether ketone (EEK) repeat units is miscible with PSF, whereas copolymers containing 12mol % EEK and more are not. COPEEK copolymers containing 6 and 12 mol % EEK are completely miscible with phenoxy, but those containing 24 mol % EEK is partially miscible with phenoxy. Moreover, a copolymer containing 17 mol % EEK is partially miscible with phenoxy; the blends show two transitions in the midcomposition region and single transitions at either extreme. Two T_gs were observed for the 50/50 blend of phenoxy with the coplymer containing 17 mol % EEK, whereas a single composition-dependent T_g appeared for all the other compositions. An FTIR study revealed that there exist hydrogen-bonding interactions between phenoxy and the copolymers. The strengths of the hydrogen-bonding interactions in the blends of the COPEEK copolymers containing 6 and 12 mol % EEK are the same as that in the phenoxy/PEK-C blend. However, for the blends of copolymers containing 17, 24, and 28 mol % EEK, the hydrogen-bonding interactions become increasingly unfavorable and the self-association of the hydroxyl groups of phenoxy is preferable as the content of EEK units in the copolymer increases. The observed miscibility was interpreted qualitatively in terms of the mean-field approach. © 1996 John Wiley & Sons, Inc.     

Structural characterization and thermal behaviour of block copolymers of polydimethylsiloxane and polyamide having trichlorogermyl pendant groups

Block copolymers having a pendant trichlorogermyl group as a part of polyamide segment? (CO? R′? CO? NH? Ar? NH? )_xCO? R′? CO? and polydimethylsiloxane of general formula [(? CO? R′? CO? HN? Ar? NH)_x? CO? R′? CO? NH(CH₂)₃SiO(CH₃)₂ ((CH₃)₂SiO)_ySi(CH₃)₂(CH₂)₃ NH? ]_n (where R′ = CH₂CH(GeCl₃), CH(CH₃)CH(GeCl₃), CH(GeCl₃)CH(CH₃); Ar = C₆H₄, (? C₆H₃? CH₃)₂, (? C₆H₃? OCH₃)₂, 2,5‐(CH₃)₂? C₆H₂, C₆H₄? O? C₆H₄) were prepared by a polycondensation reaction and characterized using CHN and Ge analysis, Fourier transform infrared (FTIR) and ¹H NMR spectroscopy, thermogravimetric analysis (TGA) and molecular weight determination. They have a lamellar structure with weight‐average molecular weight in the range 1.21 × 10⁵–4.79 × 10⁵ g mol^?1. These copolymers display two glass transition temperatures and have an average decomposition temperature of 489 °C. TGA, FTIR and gas chromatography/mass spectrometry studies indicate that degradation of these block copolymers results in carbon monoxide, oligomeric siloxanes and polyamide fragments. They are thermally stable due to the hydrogen bonded interlinked chains of polyamide, while they absorb water due to the presence of Ge? Cl bonding. Copyright © 2010 Society of Chemical Industry     

Comb-branched poly(alkyl itaconates) containing pendant ethylene amine groups

Comb-branched copolymers containing ethylene amine side chains of the general structure -NH(CH₂CH₂NH)_x? H with x=1, 2, 3 and 4, were prepared by the reaction of poly(monoalkyl-codialkyl itaconate)s, using an excess of the appropriate diamine in the presence of dicyclohexylcarbo-diimide. Incorporation of ethylene amine units in the itaconate copolymers resulted in an increase in the glass transition temperature (T_g) and in the complex modulus of the modified copolymers above T_g. Both effects were proportional to the ethylene amine content of the copolymers. Chemical modification also occurred when samples were heated to about 450 K when imide formation was detected.     

The effect of annealing at 135° on the mechanical properties of injection molded high density polyethylene-polypropylene blends

The effect of annealing at 135°C for 5 hours on the tensile properties of mechanically mixed and then injection molded high density polyethylene (HDPE) and polypropylene (PP) blends has been investigated. Both the tangent elastic modulus and the tensile strength at yield exhibit a non-linear behavior versus blend composition with a minimum of properties typical for incompatible blends. Annealing substantially improves mechanical properties of pure components and blends (20 percent increase in the yield strength of pure components and blends and the modulus of pure components, and ～40 percent increase in the modulus of 50/50 blends) but the property behavior versus composition is still nonlinear. Scanning electron microscopy studies of fracture surfaces of blends seems to indicate some improvement in bonding between phases as a result of annealing, Both the elastic modulus and yield strength fit extremely well to the modified “rule of mixtures” equation in the general form: M_b = M_PEφ_PE + M_PPφ_PP + ΔM_PE/PPφ_PEφ_PP where M_b is the blend property, M_PE and M_PP are properties of pure PE and PP components, φ_PE and φ_PP are weight fractions of PE and PP, and ΔM_PE/PP is the interaction term being a measure of the deviation from simple additivity.     

Thermotropic Liquid Crystalline Polyesters with Rigid or Flexible Spacer Groups

Several different series of rigid and flexible polyesters with main chain liquid crystalline units were prepared and their properties were examined in relation to their structures. The first group of polymers were rigid aromatic copolyesters with mesogenic groups based on either chloro or methyl hydroquinone terephthalate units combined with varying amounts of different types of bisphenol terephthalate units The bisphenol comonomers used contained the structure: in which X was none, ? C(CH₃)₂? , ? CH₂? , ? O? , ? S? , and ? So₂? . It was observed that the bisphenols with the bulkier X group were more efficient in destroying thermotropic liquid crystallinity of the resulting copolymers. The second group of polymers studied were flexible polyesters consisting of various types of mesogenic units which were connected together by different lengths of polymethylene flexible spacers. The liquid crystalline behaviours of these polymers, particularly their transition temperatures, were correlated with their structures. A brief review of previous studies on the synthesis of thermotropic liquid crystalline polyesters is included.     

Swelling behaviour of hydrogels from methacrylic acid and poly(ethylene glycol) side chains by magnetic resonance imaging

The swelling behaviour of hydrogels of methacrylic acid and poly(ethylene glycol) monomethyl ether monomethacrylate macromonomer, P[(MAA)‐co‐(PEGMEMA)], copolymers was investigated. Under pH 7, characteristic sigmoidal swelling appears depending on composition. This anomalous swelling phenomenon is related to the ability of moieties in the comonomeric units ? COOH and ? [? O? CH₂? CH₂? ]? to form complexes by hydrogen bonding, stabilized by hydrophobic interactions. The swelling was followed using magnetic resonance imaging (MRI) providing spatial and temporal resolution. Data from MRI are compared with gravimetric results and photographs during swelling. In the MRI images two processes were distinguished, corresponding to a swollen external region in contrast to a rigid core which starts to swell after a lag time depending on sample composition. Microscopic and macroscopic results are in good agreement. Copyright © 2007 Society of Chemical Industry     

Expanding the chemistry of single‐ion conducting poly(ionic liquid)s with polyhedral boron anions

The synthesis of a new family of single‐ion conducting random copolymers bearing polyhedral boron anions is reported. For this purpose two novel ionic monomers, namely [B₁₂H₁₁(OCH₂CH₂)₂OC(?O)C(CH₃)?CH₂]^2?[(C₄H₉)₄N⁺]₂ and [8‐(OCH₂CH₂)₂OC(?O)C(CH₃)?CH₂‐3,3′‐Co(1,2‐C₂B₉H₁₀)(1′,2′‐C₂B₉H₁₁)]^?K⁺, having methacrylate function, diethylene glycol bridge and closo‐dodecaborate or cobalt bis(1,2‐dicarbollide) anions were designed. Such monomers differ from previously reported ones by (i) chemically attached highly delocalized boron anions, by (ii) valency of the anion (divalent anion and monovalent one) and by (iii) the presence of oxyethylene flexible spacer between the methacrylate group and bonded anion. Their free radical copolymerization with poly(ethylene glycol) methyl ether methacrylate and subsequent ion exchange provided lithium‐ion conducting polyelectrolytes showing low glass transition temperature (?53 to ?49 °C), ionic conductivity up to 9.1 × 10^?7 S cm^?1, lithium transference number up to 0.61 (70 °C) and electrochemical stability up to 4.1 V versus Li⁺/Li (70 °C). The incorporation of propylene carbonate (20–40 wt%) into the copolymers resulted in the enhancement of their ionic conductivity by one order of magnitude and significantly increased their electrochemical stability up to 4.7 V versus Li⁺/Li (70 °C). © 2019 Society of Chemical Industry     

The effects of pressure and temperature upon the viscosities of liquids with special reference to polymeric liquids

From a consideration of the work required for expansion of a liquid, the following relationship between viscosity η, pressure P and temperature T is put forward. For unassociated liquids with molecules which are not too large, V* is taken as the parachor, log₁₀ (η* in Ns/m²) is ?3.88, P* is 8.58 × 10⁶ N/m², R is the gas constant, and T* is a constant characteristic of each liquid. The equation can be applied to polymeric liquids if V* and η* are taken as disposable constants. For example, for polystyrene V* is found to be 3 × 10^?3 m³ mol^?1 and log₁₀ (η* in Ns/m²) to be 3.4 log₁₀ M?_w ?10.2 where M?_w is the weight-average molecular weight (kg/mol) from 5 kg/mol upwards. In the equation, the same constants serve for the variation of viscosity with pressure and with temperature. The viscosity under a high pressure can therefore be estimated from viscosities all measured at normal pressures but at different temperatures. The viscosities of a number of polymers have been measured over a range of temperature and pressure and the results support the equation. Support is found for the view that segments are involved in the flow of polymeric liquids and V* gives a measure of the volume of the segment. The size of the segment seems to increase as the flexibility of the polymer chain decreases. The lowest values for V* are found for polysiloxanes in which the segment seems to be only four atoms long. Larger values of V* are found for polymers with units of the type –CH₂–CHR-. Larger values still of V* are given by polymers with units of the type –CH₂-CR₁R₂- and even larger V* values are found for those polymers with benzene rings constituting a major part of the main chain. As V* rises the viscosity of the polymeric liquid becomes much more dependent upon pressure and temperature. Thus whilst the polysiloxanes have viscosities which are relatively insensitive to pressure and temperature, the aromatic polysulphones and poly(2,6-dimethylphenylene oxide) have viscosities which are very sensitive to pressure and temperature.     

Ethylene polymerization using vanadium catalyst supported on silica modified by pyridinium ionic liquid

Vanadium catalyst systems (SIL_1–3A(B)/V) for ethylene polymerization were obtained by immobilization of the Cp₂VCl₂ precursor (V) in the ionic liquid 1‐[3‐(triethoxysilyl)propyl]pyridinium chloride (IL), modified by AlCl₃ and AlEtCl₂ (A) or AlEt₂Cl (B), and supported on three types of silica carrier S_1–3. The properties of the ionic liquid supports were determined using Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller measurements, scanning electron microscopy and elemental analysis. The best results (above 2 tons PE (mol V)^?1 (0.5 h)^?1) were obtained using the catalyst system SIL₃B/V. Addition of ethyl trichloroacetate is possible in the ionic liquid medium and it further increases the activity up to 7 tons PE (mol V)^?1 (0.5 h)^?1. In contrast, application of the imidazolium ionic liquid to the SIL system or application the analogous catalyst system without the ionic liquid results in lower activities. The obtained polyethylene (PE) is a linear polymer, with molecular weight (M_w) of over 10⁶ g mol^?1 and molecular weight distribution (M_w/M_n) in the range 1.6–1.9, and has a characteristic fluffy or fibrous shape. In contrast, the PE samples obtained using the systems without ionic liquid reveal broader M_w/M_n (2.5–3.7) and replicate the support morphology. © 2016 Society of Chemical Industry     

An effective method to identify the type and content of α‐olefin in polyolefine copolymer by Fourier Transform Infrared–Differential Scanning Calorimetry

A new method for identification of ethylene/α‐olefin copolymer was established by Fourier Transform Infared (FTIR)–Differential Scanning Calorimetery (DSC) in this article. DSC and FTIR spectroscopy techniques were used to analysis the type and content of α‐olefin in polyolefine copolymer. FTIR was available to identify the structures of polyethylene and copolymers of ethylene with different α‐olefins. The type of polyethylene can be determined by the peak position of 1378 and 1369 cm^?1. According to the peak location of 770, 784, and 895 cm^?1, the type of α‐olefin can also be determined. DSC method was used to decide the position of melting peaks. The quantitative investigation of the content of α‐olefin in polyethylene was calculated by the formula: ?ln(CH₂ mol fraction) = ?0.331+135.5/T_m. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polymer electrolyte complexes of LiCIO4 and comb polymers of siloxane with oligo-oxyethylene side chains

Polysiloxanes with oligo-oxyethylene side chains of the type —O(CH₂CH₂O)₇CH₃ and —(CH₂)₃O(CH₂CH₂O)_nCH₃ (average n ≈ 7 and 11) were synthesized from poly(hydrogenmethylsiloxane) and characterized by ¹H n.m.r., ²⁹Si n.m.r., i.r. and g.p.c. Cyclic analogues were used as model compounds and synthesized from tetramethylcyclotetrasiloxane. Polymer electrolyte complexes were made from the comb polymers and LiClO₄ by solvent-casting from THF, and their conductivities measured as a function of temperature and studied by differential scanning calorimetry and correlated with their conductivity behaviour. Maximum conductivities close to 10^?4S cm^?1 were achieved at room temperature and at ethylene oxide units to Li⁺ ratios of about 25. Cross-linking or blending with high molecular weight poly(oxyethylene) lowers the conductance somewhat but vastly improves the mechanical properties of the complexes, and the blends with PEO can be cast into thin, flexible and tough films with good conducting properties.     

Improving the antifouling properties of polypropylene surfaces by melt blending with polyethylene glycol diblock copolymers

Protein‐resistant polyethylene‐block‐poly(ethylene glycol) (PE‐b‐PEG) copolymers of different molecular weights at various concentrations were compounded by melt blending with polypropylene (PP) polymers in order to enhance their antifouling properties. Phase separation of the PE‐b‐PEG copolymer and its migration to the surface of the PP blend, was confirmed by attenuated total reflectance–Fourier transform infrared, X‐ray photoelectron spectroscopy, and static water contact angle measurements. Enrichment of PEG chains at the surface of the blends increased with increasing PE‐b‐PEG copolymer concentration and molecular weight. The PP blends compounded with PE‐b‐PEG copolymer having the lowest molecular weight (875 g mol^?1), at the lowest concentration (1 wt %), gave the lowest bovine serum protein adsorption (30% less) compared to that of neat PP. At higher concentrations (5 and 10 wt %), and higher molecular weights (920, 1400, and 2250 g mol^?1), the PE‐b‐PEG copolymers leached‐out resulting in protein adsorption comparable to that of neat PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46122.     

Grafting of polystyrene branches to polyethylene and polypropylene

Polyethylene (PE) and polypropylene (PP) were reacted with benzoyl peroxide (BPO) and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO) to prepare PE‐TEMPO and PP‐TEMPO macroinitiators, respectively. Molecular weight of PP decreased, whereas that of PE increased during the reaction with the BPO/TEMPO system. Polystyrene (PS) branches were grafted to PE and PP backbone chains as a result of bulk polymerization of styrene with the PE‐TEMPO and PP‐TEMPO macroinitiators. A significant amount of PS homopolymer was produced as a byproduct. Weight of the resulting PE‐g‐PS and PP‐g‐PS increased with the polymerization time up to 20 h and then leveled off. Melting point of PE and PP domains in PE‐g‐PS and PP‐g‐PS, respectively, lowered as the content of PS in the copolymers increased. However, glass transition of the copolymers was almost identical with that of PS homopolymer, indicating that the constituents in the copolymers were all phase‐separated from each other. In scanning electron microscopy of the incompatible PE/PS, PP/PS, and PE/PP/PS compounded with PE‐g‐PS and PP‐g‐PS, any clear indication of enhanced adhesion between the phases was not observed. However, phase domains in the blends were, nevertheless, reduced significantly to raise mechanical properties such as maximum stress and elongation at break by 20–75%. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1103–1111, 2002     

Vinyl ether‐based polyacetal polyols with various main‐chain structures and polyurethane elastomers prepared therefrom: Synthesis,structure, and functional properties

Novel acid degradable polyacetal polyols and polyacetal polyurethanes able to controlled acid degradation were developed. Polyacetal polyols with various main‐chain structures were synthesized by polyaddition of various vinyl ethers with a hydroxyl group [4‐hydroxy butyl vinyl ether (CH₂?CH? O? CH₂CH₂CH₂CH₂? OH), 2‐hydroxy ethyl vinyl ether (CH₂?CH? O? CH₂CH₂? OH), diethylene glycol monovinyl ether (CH₂?CH? O? CH₂CH₂OCH₂CH₂? OH), and cyclohexanedimethanol monovinyl ether (CH₂?CH? O? CH₂? C₆H₁₀? CH₂? OH)] with p‐toluenesulfonic acid monohydrate (TSAM) as a catalyst in the presence of the corresponding diols [1,4‐butandiol (HO? CH₂CH₂CH₂CH₂? OH), ethylene glycol (HO? CH₂CH₂? OH), diethylene glycol (HO? CH₂CH₂OCH₂CH₂? OH), and 1,4‐cyclohexanedimethanol (HO? CH₂? C₆H₁₀? CH₂? OH)], respectively. Polyacetal polyurethanes were prepared by a two‐step polymerization, using the synthesized polyacetal polyols, 4,4′‐diphenylmethane diisocyanate (MDI), and 1,4‐butandiol (BD) as a chain extender. Depending on the main‐chain structures, these polyurethanes had different glass transition temperature (from ?44 to 19 °C) and properties such as hydrophobic or hydrophilic. Polyurethanes containing the hydrophilic main‐chain exhibited the thermoresponsiveness and had the certain volume phase transition temperature (VPTT). The polyacetal polyurethanes were flexible elastomers around room temperature (～25 °C) and thermally stable (T_d ≥ 310 °C) and additionally exhibited smooth degradation with a treatment of aqueous acid in THF at room temperature to give the corresponding raw material diols. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44088.     

Preparation and characterization of melamine–formaldehyde–polyvinylpyrrolidone polymer resin for better industrial uses over melamine resins

Melamine–formaldehyde–polyvinylpyrrolidone (MFP) polymer resin was prepared with 1 : 16 : 1 ratios of melamine, formaldehyde (CH₂O), and polyvinylpyrrolidone amounts, respectively, by condensation polymerization at 6.9 pH. Structures were determined with IR, ¹H‐NMR, and ¹³C‐NMR spectroscopies. Chemical shifts (δ, ppm) were analyzed with singlet at δ 4.5, duplet from 3.13 to 3.17 and a quartet at 1.5 to 2.2 ppm for methylene (? CH₂? ) bridging group, pyrrolidone, and polyvinyl constituents. The 3389.25, 1290.38, and 1655.28 cm^?1 stretching frequencies of ? N?, ? CH? and ? C? O? O? groups, respectively, were noted on FTIR spectrum. The ? C?N? melamine units reacted with CH₂O to adjoin with polyvinylpyrrolidone (PVP). An average viscosity molecular weight ( _v) 57,000 g mol^?1 was obtained with Mark–Houwink–Sakurada equation. The chemical shift of ? N(CH₂O)₂? C? pyrrolidone ring on ¹³C‐NMR spectra was shifted toward lower magnetic field at 175.18 ppm. The resin was partially miscible with water thereby densities and viscosities of aqueous solutions were measured at 298.15 K temperature. It showed higher densities and viscosities than those of water. The resin developed exceptionally higher adhesive strengthen when its 62.29‐μm uniform thin film was applied on surfaces of wooden strips. The resin showed micellar behavior at about 0.009 g/100 mL aqueous solution. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Reactive compatibilization of poly(styrene‐ran‐acrylonitrile)/poly(ethylene) blends through the acid–epoxy reaction

Two families of acid functional styrene/acrylonitrile copolymers (SAN) for application as dispersed phase barrier materials in poly(ethylene) (PE) were studied. One type is SAN made by nitroxide mediated polymerization (NMP), which was subsequently chain extended with a styrene/tert‐butyl acrylate (S/tBA) mixture to provide a block copolymer (number average molecular weight M_n = 36.6 kg mol^?1 and dispersity ? = 1.34, after which the tert‐butyl protecting groups were converted to acid groups (SAN‐b‐S/AA). The other acid functional SAN is made by conventional radical terpolymerization (SAN‐AA). SAN‐AA and SAN‐b‐S/AA were each melt blended with PE grafted with epoxy functional glycidyl methacrylate (PE‐GMA) at 160 °C in a twin screw extruder (70:30 wt % PE‐GMA:SAN co/terpolymer). The non‐reactive PE‐g‐GMA/SAN blend had a volume to surface area diameter = 3.0 μm while the reactive blends (via epoxy/acid coupling) (PE‐GMA/SAN‐b‐SAA and PE‐GMA/SAN‐AA) had = 1.7 μm and 1.1 μm, respectively. After thermal annealing, the non‐reactive blend coarsened dramatically while the reactive blends showed little signs of coarsening, suggesting that the acid/epoxy coupling was effective for morphological stability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44178.