Crosslinking and ozone degradation of thermosetting resins based on maleic anhydride/diene copolymer and polyfunctional alcohols

Crosslinking and de‐crosslinking reactions of an alternating copolymer of maleic anhydride (MAn) and 2,4‐dimethyl‐1,3‐pentadiene (DMPD) by thermal curing with polyfunctional alcohols as the crosslinkers and subsequent ozone degradation are reported in this article. The ring‐opening reaction of an anhydride group by polyfunctional alcohols produces network polymers with an ester linkage. The rate of crosslinking reaction depends on the curing conditions, i.e. the structure of the used alcohols and the curing temperature and time. The crosslinking density of the alcohol‐cured copolymers is low due to a slow reaction between the anhydride and hydroxy groups, being different from the corresponding epoxy‐cured copolymer with a dense network structure reported in a previous article. The insoluble resins are readily de‐crosslinked and solubilized by ozone degradation. The polymer surface modification by ozone is also investigated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42763.     

Mechanical and dynamic mechanical properties of waste rubber powder/HDPE composite

Mechanical and dynamic mechanical properties of a waste rubber powder‐filled high‐density polyethylene (HDPE) composite are investigated. Rubber powder is surface‐modified with acrylamide (AAm) using ultraviolet. Rubber powder and HDPE are extruded using a single‐screw extruder and maleic anhydride‐grafted polypropylene is added as a compatibilizer to improve the adhesion between rubber powder and HDPE. The tensile stress and strain of AAm‐grafted rubber powder/compatibilizer/HDPE composites always exhibit higher values than those of unmodified rubber powder/HDPE composites. Surface modification of rubber powder is shown to decrease the magnitude of the tan δ of the HDPE composite. Higher values of the notched Izod impact strength of a surface‐modified rubber‐filled composite is observed compared to those of unmodified rubber‐filled composite. Experimental results show that acryl amide‐grafted rubber powder reacts with maleic anhydride and it results in improved mechanical properties of the HDPE composite. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2595–2602, 2000     

Effects of toughening agents on the behaviors of bamboo plastic composites

Three kinds of reactive toughening agents of bamboo plastic composites are studied in this article. The bio‐fiber keeps high polarity for the hydroxyl groups of the surface, while polypropylene (PP) matrix resin phase is nonpolar. So, the interfacial compatibility between matrix and enhanced phase is poor. The anhydride in maleic anhydride grafted polypropylene can react with the hydroxyls. A large number of hydroxyl groups on the fiber surface are reduced, and the interfacial bond strength is improved. Three reactive toughening agents: glycidyl methacrylate grafted poly(ethylene‐1‐octene), maleic anhydride grafted poly(ethylene‐octene), and poly(ethylene‐butylacrylate‐glycidyl methacrylate) are chosen to improve the impact toughness. The mechanical properties, compatibility, phase structure, water absorption, and thermal properties of PP blends are all investigated. When the content of toughening agents are controlled between 6% and 8%, not only the impact strength is greatly improved but also the other properties of PP are less affected, which makes the composites with comprehensive and practical applications. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Improving the antifouling property of polypropylene hollow fiber membranes by in situ ultrasonic wave‐assisted polymerization of styrene and maleic anhydride

For the purpose of enhancing the hydrophilicity and antifouling property, styrene‐maleic anhydride copolymer (SMA) was successfully introduced on the surface of polypropylene hollow fiber membranes via in situ ultrasonic wave‐assisted polymerization. It was shown that how to avoid the hydrolysis and esterification of anhydride groups was the key for improving the hydrophilicity and antifouling property of membranes. Some factors were studied in detail, such as solvent, concentration of solution as well as time and temperature of ultrasonic treatment. Results showed that acetone and ethanol as solvents performed different functions during the process of the polymerization, and ethanol, a polar solvent, reacted with anhydride groups to hinder the formation of SMA and improvement of antifouling property. The modified membranes (PPM1 and PPM5) exhibit both high water flux and strong antifouling capability. Besides, antifouling property of modified membranes was very stable, which proved that they can work in reality. This study supplied a new approach to fabricate highly efficient polymeric membranes applicable to wastewater purification. POLYM. ENG. SCI., 59:E51–E58, 2019. © 2018 Society of Plastics Engineers     

Synthesis of poly(ester‐anhydride)s based on poly(ϵ‐caprolactone) prepolymer

The objective of this study was to prepare high molecular weight poly(ester‐anhydride)s by melt polycondensation. The polymerization procedure consisted of the preparation of carboxylic acid terminated poly(?‐caprolactone) prepolymers that were melt polymerized to poly(?‐caprolactone)s containing anhydride functions along the polymer backbone. Poly(?‐caprolactone) prepolymers were prepared using either 1,4‐butanediol or 4‐(hydroxymethyl)benzoic acid as initiators, yielding hydroxyl‐terminated intermediates that were then converted to carboxylic acid‐terminated prepolymers by reaction with succinic anhydride. Prepolymers were then allowed to react with an excess of acetic anhydride, followed by subsequent polycondensation to resulting high molecular weight poly(ester‐anhydride)s. Upon coupling of prepolymers, size exclusion chromatography analyses showed an increase from 3600 to 70,000 g/mol in number‐average molecular weight (M_n) for the 1,4‐butanediol initiated polymer, and an increase from 7200 to 68,000 g/mol for the 4‐(hydroxymethyl)benzoic acid‐initiated polymer. 4‐Hydroxybenzoic acid and adipic acid were also used as initiators in the preparation of poly(?‐caprolactone) prepolymers. However, with these initiators, the results were not satisfactory. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 176–185, 2001     

Compatibilization of a polyolefin blend through covalent and ionic coupling of grafted polypropylene and polyethylene. I. Rheological,thermal, and mechanical properties

A polypropylene/high‐density polyethylene blend containing 70 wt % polypropylene was prepared and compatibilized via the addition of maleic anhydride grafted polypropylene and polyethylene. The functionalized polymer chains were coupled with two types of coupling agents. Dodecane diamine formed covalent bonds with the maleic anhydride, whereas two metallic salts, zinc acetate and sodium hydrogenocarbonate, formed ionic interactions with the carboxylic functions produced by the hydration of the anhydride cycle. The coupling of the grafted polyolefin chains was successfully realized by a single operation in a twin‐screw extruder. The coupling agents were efficient in improving the elongation at break and impact properties of the studied blends. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 312–320, 2005     

Preparation and luminescence of SrAl2O4: Eu2+,Dy3+ phosphors coated with maleic anhydride

In this paper, maleic anhydride is directly coated on the surface of SrAl₂O₄: Eu²⁺, Dy³⁺ (SAO‐ED) phosphors by an interfacial coordination chemistry method. Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectra (XPS), X‐ray diffraction (XRD), and scanning electron microscopy (SEM) methods are used to characterize the coating. The experimental result shows that a dense coating layer is consisting of maleic anhydride coordination with metal ions on the surface of the phosphors and the coating process does not destroy the crystal structure of the phosphors. It is also found that the introduction of maleic anhydride does not change the excitation and emission spectra of SAO‐ED phosphors, but decreases the luminous intensity, which is verified by the photoluminescence (PL) measurement. Afterglow delay curves show that the initial brightness of coated SAO‐ED phosphors decreases, but the afterglow decay rate of coated phosphors is slower than that of uncoated phosphors after they both are immersed into water for one month. This indicates that the coating layer protects the phosphors and the crystal structure of coated phosphors in water was not destroyed.     

Miscibility characterization of SMA/SAN and SMA/PMMA blends by differential scanning calorimetry and fluorescence techniques

In this study, styrene‐maleic anhydride (SMA) copolymer was modified by monoesterification method with 9‐(hydroxymethyl)anthracene fluorophore to prepare a fluorescent anthracene labeled SMA (SMA‐An) material. The latter was then characterized by attenuated total reflection (ATR) and thermogravimetric analysis (TGA) techniques. In the second step of this work, SMA‐An was added to SMA/[Styrene‐Acrylonitrile Copolymer (SAN)] and SMA/[Poly(methyl methacrylate) (PMMA)] blends to investigate the miscibility of these blends at the molecular level. The miscibility of SMA/PMMA blends was characterized using fluorescence quenching of anthracene by the succinic anhydride and succinic acid functions on SMA macromolecule itself. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Non‐catalytic anhydride curing of hydrogenated bisphenol‐A glycidyl ether with 1,2,4‐cyclohexanetricarboxylic anhydride and light emitting diode encapsulation

Noncatalytic anhydride curing of hydrogenated bisphenol‐A glycidyl ether (YX8000) using hydrogenated trimellic anhydride (1,2,4‐cyclohexanetricarboxylic anhydride, H‐TMAn) and methylhexahydrophthalic anhydride (MeHHPA) were studied. Differential scanning calorimetry data shows no exthothermal under 190°C using MeHHPA without catalyst because of the low reactivity. On the other hand, H‐TMAn had higher reactivity and it can be cured without catalyst. The effect of anhydride concentration both on curing and on properties was studied in detail. For example, the highest T_g was found when YX8000 : H‐TMAn = 100 : 75 or YX8000 : MeHHPA = 100 : 100. The highest curing exothermal was found at similar ratio. Following, the encapsulation of light emitting diode (LED) was prepared with two anhydrides. Surface volume decrease was observed with MeHHPA by its evaporation, but H‐TMAn gave flat surface. After thermal cycle test of these LED, H‐TMAn was found to have better crack resistance than MeHHPA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 962–966, 2006     

α‐Amylase immobilized by Fe3O4/poly(styrene‐co‐maleic anhydride) magnetic composite microspheres: Preparation and characterization

Fe₃O₄/poly(styrene‐co‐maleic anhydride) core–shell composite microspheres, suitable for binding enzymes, were prepared using magnetite particles as seeds by copolymerization of styrene and maleic anhydride. The magnetite particles were encapsulated by polyethylene glycol, which improved the affinity between the magnetite particles and the monomers, thus showing that the size of the microspheres, the amount of the surface anhydrides, and the magnetite content in the composite are highly dependent on magnetite particles, comonomer ratio, and dispersion medium used in the polymerization. The composite microspheres, having 0.08–0.8 μm diameter and containing 100–800 μg magnetite/g microspheres and 0–18 mmol surface‐anhydride groups/g microsphere, were obtained. Free α‐amylase was immobilized on the microspheres containing reactive surface‐anhydride groups by covalent binding. The effects of immobilization on the properties of the immobilized α‐amylase [magnetic immobilized enzyme (MIE)] were studied. The activity of MIE and protein binding capacity reached 113,800 U and 544.3 mg/g dry microspheres, respectively. The activity recovery was 47.2%. The MIE had higher optimum temperature and pH compared with those of free α‐amylase and showed excellent thermal, storage, pH, and operational stability. Furthermore, it can be easily separated in a magnetic field and reused repeatedly. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 328–335, 2005     

Improving collagen extraction through an alternative strategy based on succinic anhydride pretreatment to retain collagen's triple‐helix structure

The improvement of the extraction yield of collagen while retaining its triple‐helix structure continues to represent a significant challenge for the high‐value utilization of collagen. In this study, pigskin was pretreated by succinic anhydride via the chemical linking of additional carboxylic groups to epsilon amino groups with a conversion degree of 90.2% to obtain pretreatment acid‐pepsin‐solubilized collagen (PAPC). The pretreatment by succinic anhydride increased the tropocollagen distance from 1.39 to 1.42 nm. This permitted acid and pepsin to more easily enter into the fiber clearance and, thus, improved the collagen extraction yield by 9.6%. Furthermore, X‐ray diffraction, Fourier transform infrared spectroscopy, circular dichroism, ultrasensitive differential scanning calorimetry, and atomic force microscopy analysis demonstrated that the triple‐helix conformation of PAPC was well‐maintained. The equilibrium surface tension and isoelectric point of PAPC were 57.48 mN/m and 4.01, respectively; this suggested that the PAPC had surface activity and better solubility in a neutral pH solution. The novelty of PAPC lay in its facilitating fibroblast proliferation, and no extra cytotoxicity was introduced into the collagen after pretreatment. According to these results, our study revealed that succinic anhydride pretreatment as an alternative strategy retained the triple‐helix structure of collagen and improved its extraction ratio; this might be a feasible, yet promising paradigm for the high‐value utilization of collagen. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45424.     

Diamine coupling of maleic‐anhydride‐ modified polyethylene

The efficiency of the diamines 1,12‐diaminododecane (C₁₂N₂) and (4,4′‐methylene)bis(2,6‐diethylaniline) (MDEA) used as coupling agents for maleic‐anhydride‐grafted polyethylene (PEgMA) was compared. The effect of the miscibility of the diamines on the course of the reaction with PEgMA was investigated. The reaction in the molten state with the functional PE was run at 150 °C in an internal mixer and the resulting modified PE was characterized. The coupling agents reacted very fast, especially the aliphatic diamine. The MDEA was slower. Moreover, the reaction of the latter with the anhydride functions was not total owing to its immiscibility with PEgMA. With C₁₂N₂, the NH₂‐to‐anhydride‐function stoichiometry leading to the higher degree of coupling was 2, indicating that the imide ring was not formed at this temperature. In this case, the coupling of the PEgMA chains resulted in a highly branched structure characterized by a high viscosity of the molten polymer and a substantial insoluble PE‐rich fraction. Copyright © 2005 Society of Chemical Industry     

Compatibility effect of reactive copolymers on polypropylene/polyamide 6 blends from commingled plastic wastes

We report the compatibility effect on a recycled polypropylene/nylon (75/25) blend processed with reactive copolymers on the basis of morphological, mechanical, and rheological characteristics. Via a scanning electron microscopy investigation, we found improved surface morphologies with regular and fine domains in a recycled polypropylene/nylon (75/25) blend compatibilized with copolymers containing maleic anhydride as a reactive functional group [styrene–(ethylene/butylene)–styrene‐graft‐maleic anhydride copolymer and polypropylene‐graft‐maleic anhydride]. Large increases in both the mechanical and rheological properties with the addition of the styrene–(ethylene/butylene)–styrene‐graft‐maleic anhydride copolymer could be interpreted with respect to a specific structure at the interface, showing a strong interfacial adhesion between recycled polypropylene and nylon. To confirm the existence of this structure, we used various dynamic rheological parameters: the Cox–Merz rule, storage modulus, and phase angle. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1188–1193, 2006     

Dynamic rheology and morphology of HDPE‐fumed silica composites: Effect of interface modification

In the present study, high density polyethylene (HDPE)‐based composites containing different amounts of fumed silica (FS) were prepared by melt compounding in a corotating twin screw extruder. Polyethylene‐g‐maleic anhydride copolymer (PE‐g‐MA) containing 1 wt% maleic anhydride was used for interface modification between filler and polymer. The interaction between the surface hydroxyl groups of fumed silica nanoparticles with maleic anhydride groups of PE‐g‐MA led to a finer dispersion of the filler in the HDPE matrix. The terminal complex viscosity and terminal storage modulus were highest at 1 wt% filler loading due to widely spread network formation by FS nanoparticles. This filler network plausibly got disturbed at higher filler content and/or interface modification which was reflected in their stress relaxation behavior also. The dynamic rheological behavior of the composites was explained in terms of morphological observations. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Further investigation of polyaminoamide‐epichlorohydrin/stearic anhydride compatibilizer system for wood‐polyethylene composites

The combination of a polyaminoamide‐epichlorohydrin (PAE) resin (a paper wet strength agent) and stearic anhydride was recently reported as an effective compatibilizer system for wood‐polyethylene composites. Further investigation of this new compatibilizer system revealed that the pH value of a PAE solution, dosages of PAE and stearic anhydride, and the weight ratio of PAE to stearic anhydride had significant impacts on the compatibilization effects of the compatibilizer system. Adjusting the pH value of the PAE solution from 5.0 to 10.4 increased the strength of the resulting wood‐polyethylene composites. The highest strength of the resulting wood‐polyethylene composites was obtained at 3 wt % PAE and 3 wt % stearic anhydride. At 4 wt % or 6 wt % of a compatibilizer, this PAE‐stearic anhydride system was superior to maleic anhydride‐grafted polyethylene (MAPE), one of the most effective compatibilizers, in terms of enhancing the strength of the resulting wood‐polyethylene composites. Fourier transform infrared spectroscopy (FTIR) analysis revealed that PAE and stearic anhydride formed covalent bonding with wood flour. The compatibilization mechanisms of this PAE‐stearic anhydride compatibilizer system were investigated in detail. Water‐resistance tests indicated that the PAE‐stearic anhydride compatibilizer system increased the water‐resistance of the resulting composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 712–718, 2006     

Synthesis,degradation, and drug delivery of cycloaliphatic poly(ester anhydride)s

The high melting point of poly(1,4‐cyclohexanedicarboxylic anhydride) [poly(CHDA)] is a disadvantage, in that it is intractable in the melting process of a drug delivery system. This report relates to diols introduced into the polyanhydride main chain to decrease its melting point. Various poly(ester anhydride)s containing ethylene glycol, 1,3‐propanediol, 1,4‐butanediol, or 1,6‐hexandiol [poly(CHDA–XDO)] were synthesized by the esterification reaction and melt polycondensation. FTIR, DSC, WAXD, and intrinsic viscosity of polymers were recorded and hydrolytic degradation, as well as in vitro drug delivery, was conducted. The results show that the samples are stable in an anhydrous environment at room temperature and degrade in water following a surface erosion mechanism. The degradation period of poly(CHDA–XDO) ranged from 130 to 320 h as a result of the different diols and amounts of XDO introduced. The in vitro drug delivery gave 130–350 h of stable delivery along with the typical surface erosion mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2509–2514, 2002     

Effects of some PVC‐grafted maleic anhydrides (PVC‐g‐MAs) on the morphology,and the mechanical and thermal properties of (alfa fiber)‐reinforced PVC composites

This work studied the poly(vinyl chloride) (PVC) chemically modified with maleic anhydride (MA) through reactions in solution, using benzoyl peroxide as an initiator. Quantities of the grafted MA were determined by the titration of carboxylic acid groups derived from the anhydride functions. Estimation of the grafted MA level was also performed by using IR absorbance ratio. Increases in reaction time led to higher levels of grafted MA. The effects of three different PVCs grafted with maleic anhydride (PVC‐g‐MAs) types on the morphological, mechanical, and thermal properties of PVC/alfa (fiber) composites were examined. The interfacial properties between fiber and PVC were improved after the addition of PVC‐g‐MA, as was evident from SEM morphology study. Enhancements of the mechanical properties and thermal stability of the PVC‐g‐MA‐treated composites were strongly dependent on the amount of MA grafts. J. VINYL ADDIT. TECHNOL., 19:225–232, 2013. © 2013 Society of Plastics Engineers     

The pH‐dependent surface properties of gelatin‐alkenylsuccinic acid anhydride derived surfactants

The pH‐dependent surface properties of a gelatin–alkenylsuccinic acid anhydride derived surfactants, containing an oligopeptide residue and alkenyl groups, were studied. The surface properties examined included surface tension, contact angle, emulsifying power, and fluorescence properties. The results showed that the surface activities of gelatin derivatives and their detergent properties for T/W fabrics are improved at low pH. These improved features make gelatin‐derived surfactants suitable for use as cleaning agents for lime‐degradable substrates such as hair and wool. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Crude and modified corncobs as complexing agents for water decontamination

The ability of corncobs to retain copper ions was studied with respect to the origin of the materials (inner or outer parts of the cobs), the granulometry, the pH, and chemical modifications with maleic anhydride (MA) and succinic anhydride (SA). Esterification, characterized by Fourier transform infrared and X‐ray photoelectron spectroscopy, led to a large increase in copper retention in comparison with unmodified corncobs. The retention capacity was improved up to 6 times with SA‐modified corncobs at pH 5. The adsorption behavior of MA‐ and SA‐grafted samples, with respect to copper, appeared to be different at pH 4 and pH 5, and this was attributed to a difference in the pK_a values of the grafted carboxylic functions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 820–826, 2004     

Biocomposites Made from Short Abaca Fiber and Biodegradable Polyesters

Natural fiber‐reinforced biodegradable polyester composites were prepared from biodegradable polyesters and surface‐untreated or ‐treated abaca fibers (length ca. 5 mm) by melt mixing and subsequent injection molding. Poly(butylene succinate)(PBS), polyestercarbonate (PEC)/poly(lactic acid)(PLA) blend, and PLA were used as biodegradable polyesters. Esterifications using acetic anhydride and butyric anhydride, alkali treatment, and cyanoethylation were performed as surface treatments on the fiber. The flexural moduli of all the fiber‐reinforced composites increased with fiber content. The effect of the surface treatment on the flexural modulus of the fiber‐reinforced composites was not so pronounced. The flexural strength of PBS composites increased with fiber content, and esterification of the fiber by butyric anhydride gave the best result. For the PEC/PLA composites, flexural strength increased slightly with increased fiber content (0–20 wt.‐%) in the case of using untreated fiber, while it increased considerably in the case of using the fiber esterified by butyric anhydride. For the PLA composite, flexural strength did not increase with the fiber reinforcement. The result of soil‐burial tests showed that the composites using untreated fiber have a higher weight loss than both the neat resin and the composites made using acetylated fiber.

Flexural modulus of PBS composites as a function of fiber content.