Thermal properties and degradation behavior of poly(1,4‐butylene adipate)/modified layered double hydroxide nanocomposites

In this study, poly(1,4‐butylene adipate) (PBA)/organomodified layered double hydroxide (m‐LDH) nanocomposites were synthesized and characterized as a new material for green materials use. m‐LDH was initially prepared with magnesium nitrate hexahydrate, aluminum nitrate‐9‐hydrate, oleic acid, and sorbitol by a novel one‐step coprecipitation method to intercalate the oleic acid and sorbitol organomodifier into the interlayer of the layered double hydroxide. The solution mixing process was then applied and shown to be an efficient method for fabricating the PBA/m‐LDH nanocomposites. The m‐LDH characterized by X‐ray diffraction (XRD) showed a high interlayer spacing of 58.8 Å. The morphology and thermal properties of the PBA/m‐LDH nanocomposites were characterized with XRD, transmission electron microscopy, and thermogravimetric analysis. It was shown that the m‐LDH was well distributed in the PBA matrix and that the thermal properties of the PBA/m‐LDH nanocomposites significantly improved with a loading of 0.1 wt % m‐LDH. Finally, the biodegradability of the PBA/m‐LDH nanocomposites was tested with lipase from Pseudomonas fluorescens as a microbial catalyst. It was shown that an addition of m‐LDH up to 0.5% resulted in a significant difference in terms of the biodegradability. After 120 h of degradation, the residual weight and surface morphology of the composite films were affected by the presence of m‐LDH. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42083.     

Synthesis of acrylate polymers by a novel emulsion polymerization for adhesive applications

Pressure‐sensitive adhesives (PSAs) are viscoelastic–elastomeric materials that can adhere strongly to solid surfaces with light contact pressure and a short contact time. Polyacrylates produced by solution polymerization are used widely because of their good adhesive properties. A novel emulsion polymerization was established to improve the low physical properties of PSA on the basis of conventional poly(n‐butyl acrylate) (PBA) by emulsion polymerization. PBA latex was synthesized by the emulsion polymerization of 50 wt % n‐butyl acrylate mixed with 15 wt % ethyl acetate (EA) with Emal‐10P and Emulgen‐920 as anionic and nonionic surfactants, respectively, at 70°C. Potassium persulfate (KPS) or a combination of KPS and dicumyl peroxide (DCP) was used as the initiator. The KPS/DCP system gave a very high‐molecular‐weight PBA of a narrow molecular weight distribution with a weight‐average molecular weight/number‐average molecular weight value of 1.01–1.03 in 15 min. The PSA tape was prepared by the casting of the PSA latex onto a corona poly(ethylene terephthalate) film as an adherent to obtain a 50‐μm‐dry‐thickness film. The PSA tape produced from PBA by the novel emulsion polymerization showed better adhesive properties, such as 180° peel adhesion, shear holding power, and rolling ball tack tests according to JIS and ASTM standards, than PSA tape produced from solution polymerization. The occlusion of a small amount of EA in emulsion particles before polymerization was found to give higher properties than those of PBA prepared by the addition of EA to the PBA latex after polymerization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:413–421, 2006     

Synthesis and properties of novel end-functionalized polybutylacrylate and its metal complexes

Summary Well-defined polybutylacrylate (PBA) was prepared by atom transfer radical polymerization (ATRP). A novel end-functionalized PBA (macromolecular ligand) was synthesized via PBA bonded with thiocarbamide. Since thiocarbamide possesses strong chelating ability, end-functionalized PBA possesses some new properties such as coordination with metallic ions. After metallic ions were introduced into it, two kinds of end-functionalized PBA metal complexes were got. The structure and property of PBA, end-functionalized PBA and its metal complexes were characterized by ¹H NMR, UV, GPC, Atomic Emission Spectrometry (AES), Cyclic Voltammogram (CV) and Dielectric Constant. The results indicate that the properties of end-functionalized PBA with well-defined structure were improved greatly by introducing a small quantity of transitional metallic ions into it. The novel end-functionalized PBA metal complexes exhibit stable electrochemical activity, dielectric property and have a good prospect in many fields as functional polymer.     

Biodegradation of starch and acrylic‐grafted starch by Aspergillus niger

The biodegradation of starch and grafted starch by Aspergillus niger was examined. The grafted polymers were poly(methyl methacrylate) (PMMA) and poly(butyl acrylate) (PBA). Thermogravimetric analysis, Fourier transform infrared, and scanning electron microscopy were used to determine the morphology and degradation degree of each material. The temperature of maximum decomposition for starch decreased as enzymatic degradation proceeded, and it was completed on the 8th day of culturing in a liquid medium. Grafted samples with PMMA and PBA achieved degradation of their starch moiety. PBA in starch‐g‐PBA samples hindered the accessibility of the enzymes to the degradable material, and this resulted in a longer degradation time. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2764–2770, 2003     

Synthesis,characterization and properties of clay‐polyacrylate hybrid materials

A new type of hybrid material of clay with poly (butyl acrylate) (PBA) has been prepared successfully using intercalation‐polymerization process. The structure of the composite was investigated by X‐ray diffraction (XRD), Fourier transform infrared (FTIR), Transmission electron microscope (TEM), and Thermogravimetric analysis (TGA). The results show that the hybrid material prepared has a decomposition central temperature of 485.6°C, 83°C higher than that of pure PBA (402.0°C). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 796–801, 2000     

Synthesis of polystyrene/poly(butyl acrylate) core–shell latex and its surface morphology

A polystyrene (PS)/poly(butyl acrylate) (PBA) composite emulsion was produced by seeded emulsion polymerization of butyl acrylate (BA) with PS seed particles which were prepared by emulsifier‐free polymerization of styrene with potassium persulfate (KPS) under a nitrogen atmosphere at 70°C for 24 h with stirring at 60 rpm and swelled with the BA monomer in an ethanol/water medium. The structure of the PS/PBA composite particles was confirmed by the presence of the characteristic absorption band attributed to PS and PBA from FTIR spectra. The particles for pure PS and PS/PBA with a low content of the BA monomer were almost spherical and regular. As the BA monomer content was increased, the particle size of the PS/PBA composite particles became larger, and more golf ball‐like particles were produced. The surface morphology of the PS/PBA composite particles was investigated by AFM and SEM. The T_g's attributed to PS and PBA in the PS/PBA composite particles were found at 110 and ?49°C, respectively. The thermal degradation of the pure PS and PS/PBA composite particles occurred in one and two steps, respectively. With an increasing amount of PBA, the initial thermal decomposition temperature increased. On the contrary the residual weight at 450°C decreased with an increasing amount of PBA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 595–601, 2003     

Core—shell structured latex particles. II. Synthesis and characterization of poly(n-butyl acrylate)/poly(benzyl methacrylate—styrene) structured latex particles

The synthesis of structured latex particles involved the preparation of a slightly crosslinked poly(n-butyl acrylate) (PBA) seed and a poly(benzyl methacrylate-styrene) [P(BM-St)] shell. It was found that structured core-shell latex particles prepared by semicontinuous monomer addition yielded better coverage of the seed particles than those polymerized by batch and that poly(benzyl methacrylate) yielded better coverage than polystyrene (PS). Polymerizations in the presence and absence of a chain transfer agent indicated that the presence of isooctyl mercaptopropionate (IOMP) causes the second-stage monomer to polymerize as an isolated, single patch of shell material. In the absence of IOMP, smaller patches of shell material are spread throughout the PBA seed surface. The different morphologies obtained under different polymerization conditions were attributed to thermodynamic and kinetic factors such as polymer-polymer interfacial tensions and viscosity effects. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of poly(butyl acrylate)/silica and poly(butyl acrylate)/silica/poly(methyl methacrylate) composite particles

Poly(butyl acrylate)/poly(methyl methacrylate) (PBA/PMMA) core–shell particles embedded with nanometer‐sized silica particles were prepared by emulsion polymerization of butyl acrylate (BA) in the presence of silica particles preabsorbed with 2,2′‐azobis(2‐amidinopropane)dihydrochloride (AIBA) initiator and subsequent MMA emulsion polymerization in the presence of PBA/silica composite particles. The morphologies of the resulting PBA/silica and PBA/silica/PMMA composite particles were characterized, which showed that AIBA could be absorbed effectively onto silica particles when the pH of the dispersion medium was greater than the isoelectric potential point of silica. The critical amount of AIBA added to have stable dispersion of silica particles increased as the pH of the dispersion medium increased. PBA/silica composite particles prepared by in situ emulsion polymerization using silica preabsorbed with AIBA showed higher silica absorption efficiency than did the PBA/silica composite particles prepared by direct mixing of PBA latex and silica dispersion or by emulsion polymerization in which AIBA was added after the mixing of BA and silica. The PBA/silica composite particles exhibited a raspberrylike morphology, with silica particles “adhered” to the surfaces of the PBA particles, whereas the PBA/silica/PMMA composite latex particles exhibited a sandwich morphology, with silica particles mainly at the interface between the PBA core and the PMMA shell. Subsequently, the PBA/silica/PMMA composite latex obtained had a narrow particle size distribution and good dispersion stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3425–3432, 2006     

An investigation on the effect of phenylboronic acid on the processibilities and thermal properties of bis-benzoxazine resins

Benzoxazine resins (BZs) as a novel type of phenolic resin are high-performance matrix resin for advanced composites. Yet there still exist some deficiencies when used as ablative material in aerospace applications, such as high curing temperature and poor thermal stability. In the present study, the phenylboronic acid (PBA) modified BZs (PBBZs) exhibiting excellent processibilities and thermal properties were prepared by incorporating PBA into BZ. The viscosity, gel time and curing behaviors were examined to demonstrate that PBBZs possessed better processibilities than the BZ, representing the catalytic effect of PBA in this case. The incorporation of PBA accelerated the ring-opening polymerization of BZ, leading to the lower curing temperature. TGA results reveal that the cured PBBZs exhibit excellent thermal properties, where the char yield at 800 °C (nitrogen atmosphere) reaches 63.7% and is increased by 14.1 percentage points than that of BZ. The formed phenylboronates during curing act as additional cross-linking points and increase the cross-linking density of the cured resin, which results in the enhancement of the glass transition temperature of BZ ranging from 165 °C to 219 °C. This study provides a new vision for the preparation of high-performance matrix resin for ablative materials by introducing aryl-boron backbone.     

Polymorphism and spherulite morphology of poly(1,4‐butylene adipate)/organically‐modified layered double hydroxide nanocomposites

A novel biodegradable poly(1,4‐butylene adipate)/organically‐modified layered double hydroxide (PBA/m‐LDH) nanocomposites are synthesized using the solution mixing process. The m‐LDH is originally prepared with magnesium nitrate hexahydrote (Mg(NO₃)₂ 6H₂O), aluminum nitrate‐9‐hydrate (Al(NO₃)₃ 9H₂O), oleic acid, and sorbitol by a novel one‐step co‐precipitation method to intercalate the organo‐modifier of oleic acid and sorbitol into the interlayer of LDH. The structure and morphology of the PBA/m‐LDH nanocomposites are characterized using X‐ray diffraction and transmission electron microscopy (TEM). It has been shown that the m‐LDH is exfoliated and well distributed in PBA matrix. The effect of m‐LDH on the polymorphic crystal and morphology of PBA at various crystallization temperatures (T_cs) would be investigated using WAXD and POM. Both data indicate that the addition of m‐LDH can change the starting formation temperature of α‐form crystals. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42526.     

Synthesis and characterization of sequential interpenetrating polymer networks of polyurethane acrylate and polybenzoxazine

High‐performance ultraviolet (UV) curable polyurethane acrylate (PUA) coating alloyed with thermally curable polybenzoxazine (PBA) is developed. The hybrid polymer networks of PUA and PBA‐a were prepared by sequential cure methods, i.e., UV cure of the PUA followed by thermal cure of the PBA fraction. The effects of sequential cure were investigated in terms of mechanical, thermal, and physical properties of the resulting polymer alloys. The fully cured PUA/PBA‐a alloy films showed only single glass transition temperature (T_g) suggesting high compatibility between the two polymer networks, possibly of an interpenetrating polymer network type. The storage modulus in a glassy state and T_g of PUA/PBA‐a alloys were found to substantially increase with increasing PBA‐a content. Furthermore, degradation temperature at 10% weight loss of the PUA/PBA‐a alloy films was relatively high whereas the char yield at 800°C was found to increase with a PBA‐a component. Hardness was enhanced, whereas water absorption and water vapor permeation rate of the alloy were suppressed by the incorporation of the PBA‐a into the polymer alloys. As a consequence, the properties of UV curable PUA networks can be positively tailored and enhanced by forming hybrid network with PBA‐a. POLYM. ENG. SCI., 54:1151–1161, 2014. © 2013 Society of Plastics Engineers     

Particle size effect on the film‐forming process of PS/PBA composite latexes

In this work, the effect of hard particle size and blend ratio on the film formation behavior of hard polystyrene (PS) and soft poly(n‐butyl acrylate) (PBA) latex blends was studied by means of steady‐state fluorescence and UV–visible techniques in conjunction with atomic force microscopy. Three different sets of latexes were synthesized: PBA latex (diameter 97 nm), pyrene (P)‐labeled large PS (LgPS; diameter 900 nm), and small PS (SmPS; diameter 320 nm). Two different series of latex blends (LgPS/PBA and SmPS/PBA) were prepared with varying blend composition at room temperature separately. Films were then annealed at elevated temperatures above glass transition (T_g) temperature of PS. Fluorescence intensity (I_P) from P and photon transmission intensity (I_tr) were measured after each annealing step to monitor the stages of film formation. The results showed that a significant change occurred in I_P and I_tr at a certain critical weight fraction (R_c) of PBA. Below R_c, two distinct film formation stages, which are named as void closure and interdiffusion, were seen. However, at PBA concentrations nearer to or above R_c, no film formation can be achieved. Comparing to the LgPS/PBA, the sintering process of SmPS/PBA particles occurred at much lower temperatures. Film formation stages for R < R_c were modeled, and related activation energies were calculated. Void closure (ΔH) and interdiffusion (ΔE) activation energies for SmPS/PBA were also found smaller in comparing with LgPS/PBA series. However, ΔH and ΔE values were not changed much with the blend composition for both series. POLYM. COMPOS., 31:1637–1652, 2010. © 2009 Society of Plastics Engineers     

Chlorohydrin water‐swellable rubber compatibilized by an amphiphilic graft copolymer. II. Effects of PVA‐g‐PBA and CPA on water‐swelling behaviors

A water‐swellable rubber (WSR), compatibilized by the amphiphilic graft copolymer, has been prepared by blending chlorohydrin rubber (CHR) with crosslinked polyacrylate (CPA), Poly(vinyl alcohol)‐g‐poly(butyl acrylate) (PVA‐g‐PBA), precipitated silica (PSA), and poly(ethylene glycol) (PEG). The WSR was characterized by scanning electron micrography (SEM). The dependence of the water‐absorbing ratio by weight, the water‐swelling ratio by volume, and the percentage loss by weight on PVA‐g‐PBA and crosslinked polyacrylate contents was investigated. The effect of PVA‐g‐PBA and crosslinked polyacrylate contents on second water‐swelling behaviors and long‐term water‐retention behaviors were also studied. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3145–3152, 1999     

Preparation of Acid Dye Molecule Surface-Imprinted Material for Effective Removal of Acid Dyes from Water and Study on its Molecule Recognition Performance

An acid dye molecule surface-imprinted material was prepared successfully for the dye removal from water by using a novel molecular surface-imprinting technique. The cationic monomer acryloyloxyethyl trimethyl ammonium chloride (DAC) was used as functional monomer, and sunset yellow was used as a model compound of water-soluble acid dyes. In the aqueous solution, DAC molecules were combined around sunset yellow molecules via electrostatic interaction. The graft/cross-linking copolymerization of DAC and the crosslinker on SiO₂ particles was initiated by a surface-initiating system of –NH₂/S₂O₈^2-, resulting in the sunset yellow molecule surface-imprinted material MIP-PDAC/SiO₂. MIP-PDAC/SiO₂ possesses special recognition property for sunset yellow.     

Dynamic mechanical properties of poly(vinyl chloride) and polyurethane carboxylate blends

The miscibility of thermoplastic polyurethane elastomers (TPUs) with poly(vinyl chloride) (PVC) was studied. PVC blends with TPUs, prepared from 4,4-diphenylmethane diisocyanate as diisocyanate, hydroxy-terminated poly(butylene adipate) (PBA) as the soft segment, and dimethylolpropionic acid as the chain extender carrying a latent anionic site for neutralization by triethylamine, showed a single glass transition temperature (T_g), irrespective of neutralization of latent anionic sites of TPU. But in neutralized TPU/PVC blends, limited intimate segmental mixing was perceived from the mechanical properties observed. When hydroxy-terminated poly(propylene glycol) was used as the soft segment instead of hydroxy-terminated PBA, PVC/TPU blends showed two separate T_g's of PVC and TPU, irrespective of neutralization. © 1994 John Wiley & Sons, Inc.     

Crystallization behavior and polymorphism of poly(1,4‐butylene adipate): Effect of anhydrous orotic acid as nucleating agent

The effect of anhydrous orotic acid (OA), as a biocompatible nucleating agent (NA), on the non‐isothermal and isothermal crystallization behaviors, polymorphic crystalline structure and phase transition of poly(1,4‐butylene adipate) (PBA) was investigated. It is found that the OA increased the crystallization temperature of the PBA in the non‐isothermal crystallization process and decreased the crystallization time of the PBA in the isothermal crystallization process. Meanwhile, the spherulite size decreased and spherulite density increased for the PBA. The OA favored the formation of the PBA α‐form crystal, compared to the neat PBA. In addition, upon incorporation of the OA, the β‐to‐α phase transition rate was enhanced significantly. Mechanisms for the preferential formation of the PBA α‐form crystal and the accelerated phase transition have also been proposed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42957.     

Surface modification of TiO2 nanoparticles with silane coupling agent for nanocomposite with poly(butyl acrylate)

Abstract

In order to enhance the compatibility of TiO₂ nanoparticles in poly(butyl acrylate) (PBA) matrix, surface modification of TiO₂ was conducted using 3-methacryloxypropyl-trimethoxysilane (MPS). To improve the effect of surface modification, TiO₂ was predispersed in ethanol via ultrasonic waves. The process was investigated in detail to obtain the optimum condition of ultrasonic dispersion. The dispersion of TiO₂ in ethanol was evaluated via sedimentation rate. Fourier transform infrared spectroscopy and thermogravimetric analysis were performed to investigate the effect of surface modification. It was found that the organic functional groups of MPS had been successfully grafted onto the surface of TiO₂ nanoparticles. Finally, both neat PBA film and TiO₂/PBA composite film were prepared and characterised. The modified TiO₂ presented good compatibility in PBA matrix.     

Effects of α‐form or β‐form nuclei on polymorphic crystalline morphology of poly(butylene adipate)

The effects of α‐form and β‐form nuclei on polymorphic morphology of poly(butylene adipate) (PBA) upon recrystallization from the molten state up to various T_max values were examined by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and polarized light microscopy (PLM). In this study, PBA with complex melting and polymorphism behaviour was used as a model for examining different types and extents of residual nuclei. As the PBA initially containing the sole α‐crystal was brought to a molten state of various T_max, the extents of trace α‐form crystal nuclei varied and were dependent on T_max. Furthermore, it did not matter whether, initially, the PBA contained α‐ or β‐form crystals (or both) because only a single type of α‐nuclei could be left upon treatment to the molten liquid state at T_max. Therefore, only the α‐crystal in PBA had ‘memory capacity’ in the molten liquid state while the β‐crystal did not. This was so because the latter had been completely transformed into the solid state prior to being heated into a liquid. PBA crystallized before α‐nuclei could be packed into α‐crystal, regardless of the crystallization temperature (T_c). For recrystallization from molten PBA without any nuclei, the crystalline polymorphism was correspondingly influenced by T_c. Copyright © 2005 Society of Chemical Industry     

Dynamic mechanical,rheological, and morphological studies of polyacrylate-graft-poly (vinyl chloride) suspension resin

A series of polyacrylate-graft-poly (vinyl chloride) (ACR-g-PVC) resins were prepared through suspension graft copolymerization. Three kinds of polyacrylate latices were grafted by vinyl chloride using suspension polymerization method at 57 ± 0.1°C, respectively. The dynamic mechanical and rheological properties and the morphology of the resulting ACR-g-PVC resins were investigated. Poly (butyl acrylate)-graft-poly (vinyl chloride) (PBA-g-PVC) resin exhibited better toughness, and the optimized content of PBA in ACR-g-PVC resin was 6–8 wt%. The melt viscosity of ACR-g-PVC resin was much lower than that of pure PVC. The nature of the fracture surfaces of ACR-g-PVC material indicated that it has good toughness. The impact strength of the PBA-g-PVC material was greatly improved compared with that of pure PVC. The Young's modulus of the ACR-g-PVC material containing less than 15 wt% of PBA was comparable to that of pure PVC according to their dynamic mechanical analysis curves. For all of the ACR-g-PVC resins, there were two individual relaxations in the low-temperature range. One was β transition of PVC, and the other was α transition of ACR. The glass transition temperature of PVC in the ACR-g-PVC resin shifted to lower temperature when the content of the PBA was above 50 wt%. POLYM. ENG. SCI., 47:996–1003, 2007. © 2007 Society of Plastics Engineers     

Preparation of molecularly imprinted fluorescence sensor based on carbon quantum dots via precipitation polymerization for fluorescence detection of tetracycline

A facile and effective method was proposed to prepare the molecularly imprinted fluorescence sensor with carbon quantum dots, which were modified vinyl groups by acrylic acid on the surface. The obtained fluorescence composite material was investigated by transmission electron microscope and Fourier transform infrared spectra. After the experimental conditions were optimized, a linear range of 1.0–60 μmol L⁻¹ was obtained and the detection limit was 0.17 μmol L⁻¹. The novel fluorescence sensor can be successfully used to detect tetracycline in real samples. This study provides a convenient strategy for selective recognition and rapid detection of tetracycline in the complex environment.