Maleic Anhydride Groups Research Articles

Preparation and Characterization of Poly (Styrene-Co-Maleic Anhydride)-Modified Boron Particles

The surface modification of boron powder with poly (styrene-co-maleic anhydride) (SMA) has been achieved through the reactions between the hydroxy groups on the surface of boron and the maleic anhydride groups in SMA. This novel polymerically modified boron was characterized using IR, TGA, TEM, and laser grain size analyzer. Experimental results from IR analysis indicated that the surface of boron was successfully modified by SMA, and TGA data analysis indicated that the amount of SMA on the boron surface was about 10% of this modified boron. TEM images of this surface modified boron indicated that the morphology of boron after modification has also been changed from an aggregated form to separated particles. The average particle size of the boron after modification was significantly increased from 2.7 to 3.7 µm in ethanol, which was obtained from the laser grain size analysis. The solvent dispersion of this modified boron was also tested. Experimental result indicated that this polymerically modified boron powder could form a well dispersed and stable suspension in chloroform due to presence of poly (styrene-co-maleic anhydride) on the surface of boron.

Renewable elastomers based on blends of maleated polypropylene and plasticized starch

AbstractMost recent developments in polymers from renewable resources have focused on thermoplastics, whereas there has been no comparable development of plastics with elastomeric properties. Here we evaluate the possibility of developing renewable elastomers based on starch. Potato starch plasticized with glycerol (called plasticized starch, or PLS) was melt‐blended with small quantities (5 wt % or 15 wt%) of maleated polypropylene (MAPP). The maleic anhydride groups of the polypropylene are expected to react with the hydroxy groups of starch under melt blending conditions. The resulting blends of MAPP and PLS were characterized by mechanical testing, SEM, DMA, and DSC. SEM, solubility and adhesion tests indicate that the blends are two‐phase materials, in which the continuous phase PLS is physically crosslinked by polypropylene domains. The materials showed rubbery properties as judged by a low glass transition temperature (∼−50°C independent of polypropylene content), and a wide rubbery plateau in DMA experiments that extended from room temperature to as high as 170°C. The tensile properties are also characteristic of elastomers. However, slow aging due to starch crystallization, and extraction of glycerol upon water exposure remain two challenges that must be overcome before the materials can be used as practical elastomers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Effect of Polyethylene Functionalization on Mechanical Properties and Morphology of PE/SiO2 Composites

In this study composites of high density polyethylene (HDPE) with various SiO2 content were prepared by melt compounding using maleic anhydride grafted polyethylene (PE-g-MAH) as a compatibilizer. The composites containing 2, 4 and 6% by weight of SiO2 particles were melt-blended in a co-rotating twin screw extruder. In all composites, polyethylene-graft-maleic anhydride copolymer (PE-g-MAH, with 0.85% maleic anhydride content) was added as a compatibilizer in the amount of 2% by weight. Morphology of inorganic silica filler precipitated from emulsion media was investigated. Mechanical properties and composite microstructure were determined by tensile tests and scanning electron microscopy technique (SEM). Tensile strength, yield stress, Young's modulus and elongation at break of PE/SiO2 composites were mainly discussed against the properties of PE/PE-g-MAH/SiO2 composites. The most pronounced increase in mechanical parameters was observed in Young's modulus for composites with polyethylene grafted with maleic anhydride. The increase in the E-modulus of PE/PE-g-MAH/SiO2composites was associated with the compatibility and improvement of interfacial adhesion between the polyethylene matrix and the nanoparticles, leading to an increased degree of particle dispersion. This finding was verified on the basis of SEM micrographs for composites of PE/PE-g-MAH/4% by weight of SiO2. The micrographs clearly documented that addition of only 2 wt% of the compatibilizer changed the composite morphology by reducing filler aggregates size as well as their number. Increased adhesion between the PE matrix and SiO2 particles was interpreted to be a result of interactions taking place between the polar groups of maleic anhydride and silanol groups on the silica surface. These interactions are responsible for reduction of the size of silica aggregates, leading to improved mechanical properties.

Effective method for dispersing SiO2 nanoparticles into polyethylene

AbstractAn effective solution mixing method starting from a synthesis solution of SiO2 nanoparticles was developed for dispersing nanoparticles into high‐density polyethylene (HDPE). Spherical SiO2 nanoparticles with narrow size distribution (50–100 nm) were prepared by Stöber method, and solvents of the synthesis solution (EtOH/NH4OH) were gradually replaced with toluene by evaporation under reduced pressure. The SiO2 nanodispersion, in toluene and residual ethanol, was mixed and refluxed with dissolved maleic anhydride grafted polyethylene (PEgMA) at a relatively high SiO2 content (17.8 wt %). The PEgMA‐SiO2 masterbatch was filtered, dried under vacuum, and mixed with HDPE by melt compounding. SiO2 contents in the final HDPE nanocomposites were 3 and 5 wt %. SEM images of the masterbatch and final composites showed the SiO2 nanoparticles to be well dispersed in HDPE. No agglomerates were observed. FTIR results suggest that the interactions between the maleic anhydride group of PEgMA and hydroxyl groups of SiO2 surface involve ester and/or hydrogen bonding. Addition of SiO2 particles and PEgMA to HDPE slightly increased Young's modulus, tensile strength, breaking strength, and elongation at break, indicating enhanced toughness of the nanocomposites. The measured Young's moduli of HDPE‐PEgMA‐SiO2 composites agreed well with Young's moduli predicted by Mori‐Tanaka composite theory. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Effects of addition of acrylic compatibilizer on the morphology and mechanical behavior of amorphous polyamide/SAN blends

AbstractAmorphous polyamide (aPA)/acrylonitrile‐styrene copolymer (SAN) blends were prepared using methyl methacrylate‐maleic anhydride copolymer MMA‐MA as compatibilizer. The aPA/SAN blends can be considered as a less complex version of the aPA/ABS (acrylonitrilebutadiene‐styrene) blends, due to the absence of the ABS rubber phase in the SAN material. It is known that acrylic copolymer might be miscible with SAN, whereas the maleic anhydride groups from MMA‐MA can react in situ with the amine end groups of aPA during melt blending. As a result, it is possible the in situ formation of aPA‐g‐MMA‐MA grafted copolymers at the aPA/SAN interface during the melt processing of the blends. In this study, the MA content in the MMA‐MA copolymer and its molecular weight was varied independently and their effects on the blend morphology and stress–strain behavior were evaluated. The morphology of the blends aPA/SAN showed a minimum in the SAN particle size at low amounts of MA in the compatibilizer, however, as the MA content in the MMA‐MA copolymer was increased larger SAN particle sizes were observed in the systems. In addition, higher MA content in the compatibilizer lead to less ductile aPA/SAN blends under tensile testing. The results shown the viscosity ratio also plays a very important role in the morphology formation and consequently on the properties of the aPA/SAN blends studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

6507 Catumaxomab treatment in gastric-cancer patients with malignant ascites – subgroup-analysis of a pivotal trial

Electrospun and ethanol-dispersed polystyrene-poly(styrene-co-maleic anhydride) (PS-PSMA) nanofibers (NFs) were used as a platform for the selective capture and three-dimensional culture of EpCAM-positive cells in cell culture medium and whole blood. The NFs were treated with streptavidin to facilitate bond formation between the amino groups of streptavidin and the maleic anhydride groups of the NFs. A biotinylated anti-EpCAM monoclonal antibody (mAb) was attached to the streptavidin-conjugated NFs via the selective binding of streptavidin and biotin. Upon simple mixing and shaking with EpCAM-positive cancer cells in a wide concentration range from 10 to 1000,000 cells per 10 mL, the mAb-attached NFs (mAb-NFs) captured the Ep-CAM positive cells in an efficiency of 59%-67% depending on initial cell concentrations, with minor mechanical capture of 14%-36%. Captured cells were directly cultured, forming cell aggregates, in the NF matrix, which ensures the cell proliferation and follow-up analysis. Furthermore, the capture capacity of mAb-NFs was assessed in the presence of whole blood and blood lysates, indicating cluster formation that captured target cells. It is anticipated that the antibody-attached NFs can be employed for the capture and analysis of very rare EpCAM positive circulating cancer cells.

Charging Nanowalls: Adjusting the Carbon Nanotube Isoelectric Point via Surface Functionalization

Controlling the point of zero charge (PZC) of carbon nanotubes is important for depositing finely dispersed metal nanoparticles from precursors in solution for fabricating chemical and biological sensor and catalyst surfaces. HiPco single-walled carbon nanotubes (p-SWNTs) were functionalized with carboxylic acid (COOH-SWNT), nitroso (NO-SWNT), and maleic anhydride (MA-SWNT) groups. The presence of attached moieties on the carbon nanotube surface was verified using X-ray photoelectron (XPS) and attenuated total reflection infrared (ATR-IR) spectroscopies. PZC measurements (in parentheses) were in the descending order: NO-SWNTs (7.5) > p-SWNTs (3.5) > MA-SWNTs (2.0) > COOH-SWNTs (1.2). The trend in measured PZC values correlated with the electron withdrawing character of the attached moieties, consistent with Hammett σ constants. Variations in the electron withdrawing character of the moieties led to SWNTs with differing semiconducting character, as observed in the UV−vis-NIR E11 semiconducting region and R...

Electrospun microfibrous poly(styrene- alt-maleic anhydride)/poly(styrene- co-maleic anhydride) mats tailored for enzymatic remediation of waters polluted by endocrine disruptors

Novel bicomponent microfibrous mats containing targeted amount of reactive maleic anhydride groups were prepared by electrospinning of mixed solutions of poly(styrene- alt-maleic anhydride) and poly(styrene- co-maleic anhydride). Then, amino-functionalized P(St- alt-MA)/P(St- co-MA) mats were obtained by reaction with p-phenylenediamine. ATR-FTIR and XPS spectroscopy were used to characterize pristine and modified P(St- alt-MA)/P(St- co-MA) mats. On the next step, laccase from Trametes versicolor was covalently attached onto the modified mats; the average amount of immobilized enzyme was 40 ± 0.7 mg/g mat. The catalytic activity of the immobilized enzyme was studied in respect to bisphenol A (BPA) endocrine disruptor. The optimum activity of the immobilized enzyme was reached at maximum flow rate of 1.3 mL/s. After 90 min the BPA concentration was reduced by 60% and the catalytic activity of microfibrous mats remained stable for about 30 successive reuses. In addition, the relative activity of laccase immobilized on the microfibrous mats was displayed in a broader pH range as compared to that of the free one.

Physicochemical Studies on Interaction Behavior of Potato Starch Filled Low Density Polyethylene Grafted Maleic Anhydride and Low Density Polyethylene Biodegradable Composite Sheets

Study presents compatibility behavior of polar group potato starch and non-polar LDPE using 50%, 0.5% maleated LDPE. The aim was to improve intermolecular interaction between two different types of moieties (LDPE and Potato Starch). Samples were prepared by mixing potato starch (upto 30% by weight) with LDPE and LDPE-grafted maleic anhydride in a single step twin screw extruder having vent zone. XRD and DSC results suggested that maleic-anhydride group of LDPE helped the interaction with starch and brought two chemical moieties closer to each other. FTIR results also strongly supported new bond formation between two chemical moieties.

Grafting of polyamide 6 on a styrene–acrylonitrile maleic anhydride terpolymer: melt rheology at the critical gel state

In this work, we studied the melt rheology of multigraft copolymers with a styrene–acrylonitrile maleic anhydride (SANMA) terpolymer backbone and randomly grafted polyamide 6 (PA 6) chains. The multi-grafted chains were formed by interfacial reactions between the maleic anhydride groups of SANMA and the amino end groups of PA 6 during melt blending. Because of the phase separation of SANMA and PA 6, the grafted SANMA backbones formed nearly circular domains which were embedded in the PA 6 melt with a diameter in the order of 20 to 40 nm. The linear viscoelastic behaviour of PA 6/SANMA blends at a sufficiently large SANMA concentration displayed the characteristics of the critical gel state, i.e. the power relations G′ ∝ G′′ ∝ ω 0.5. In elongation, the PA 6/SANMA blend at the critical gel state showed a non-linear strain hardening behaviour already at a very small Hencky strain. In contrast to neat PA 6, the elasticity of the PA 6/SANMA blends was strongly pronounced, which was demonstrated by recovery experiments. Rheotens tests agreed with the linear viscoelastic shear oscillations and the measurements using the elongational rheometer RME. Increasing the SANMA concentration led to a larger melt strength and a reduced drawability. The occurrence of the critical gel state can be interpreted by the cooperative motion of molecules which develops between the grafted PA 6 chains of neighbouring micelle-like SANMA domains.

Polypropylene/silica nanocomposites prepared by in‐situ melt ultrasonication

AbstractA novel process using ultrasonic irradiation to enhance nanosilica dispersion in polypropylene‐based nanocomposites has been proposed and investigated. The nanocomposites were isotactic polypropylene reinforced with silica nanoparticles at 3 wt% loading level. Ultrasonic processing in the melt state is an effective method for improving nanosilica dispersion. The effectiveness of the proposed ultrasonic processing technique on polypropylene nanocomposites was evaluated by XRD and transmission electron microscopy (TEM). Poly(propylene‐g‐maleic anhydride) copolymer (PP‐g‐MAH) containing 5 wt% maleic anhydride content was added to nanocomposites at 0.5 wt% concentration based on silica content. PP‐g‐MAH plays an important role in nanosilica dispersion in polymer matrix and interface interaction. The reaction of maleic anhydride groups with the hydroxyl groups on the surface of nanosilica was characterized by FTIR spectrum. The final nanocomposites result in a further enhancement of mechanical properties because of silica agglomerate reduction and improving interface combination, even loading level being much lower than that of ordinary fillers in conventional composites. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers

Polypropylene nanocomposite using maleated PP and diamine

The insertion of the aliphatic diamine inside the organoclay will help the dispersion of the clay platelets in the PP/clay nanocomposite due to the reaction between the maleated PP and the diamine. Cloisite®20A was just simply mixed with hexamethylene diamine (HMDA) under shearing condition in Brabender mixer. HMDA group was successfully penetrated into silicate layers. As a result of penetration, d-spacing of organoclay was increased. Polypropylene/clay nanocomposites were prepared by compounding with maleated PP and amine-treated clay. From the FTIR spectra, reaction between amine group and maleic-anhydride group was confirmed. The effect of the organoclay on the properties of the nanocomposite such as the morphology, dynamic mechanical properties, crystal structure and crystallization behavior, glass transition temperature, thermal stability, and tensile properties were investigated and analyzed. Nanocomposites with amine-treated clays show enhanced properties compared with those with non–amine-treated clay (Cloisite®20A). From the TEM analysis, nanocomposites with amine-treated clays shows better dispersibility compared with those with Cloisite®20A alone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Thermodynamic study of surfaces of liquid polybutadienes and their interfaces with poly(dimethylsiloxane)

AbstractSurface tension of liquid polybutadienes (PBD) as well as interfacial tension between them and poly(dimethylsiloxane) (PDMS) were measured in the temperature range from 25 to 150°C. The measured pressure–volume–temperature (PVT) data were used for the determination of reduction parameters of pressure, volume, and temperature in several equations of state for polymers. The reduction parameters were used for the estimates of surface tension and compared with experimental data. Interfacial tensions were used to determine Flory‐Huggins interaction parameters using the Roe and Helfand theories for the system PBD‐PDMS. The results obtained using both the theories were somewhat different; the difference being the least with the segment chosen as a part of molecule containing 4–5 nonhydrogen atoms.Modifications of PBD that were investigated increase the density. Maleic ester end groups increase both surface tension and interfacial tension and bring a positive contribution to the Flory‐Huggins interaction parameter (to its enthalpic component), whereas the pending maleic anhydride groups have shown the opposite effect; their negative contribution to Flory‐Huggins parameters concerns mainly its entropic component. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Influence of chain extension on the compatibilization and properties of recycled poly(ethylene terephthalate)/linear low density polyethylene blends

Polymeric methylene diphenyl diisocyanate (PMDI) was added as chain extender to a blend of recycled poly(ethylene terephthalate) (R-PET) and linear low density polyethylene (LLDPE) with compatibilizer of maleic anhydride- grafted poly(styrene–ethylene/butadiene–styrene) (SEBS- g-MA). Hydroxyl end groups of PET can react with both isocyanate groups of PMDI and maleic anhydride groups of SEBS- g-MA, which are competing reactions during reactive extrusion. The compatibility and properties of the blends with various contents of PMDI were systemically evaluated and investigated. WAXD results and SEM observations indicated that chain extension inhibits the reaction between PET and SEBS- g-MA. As the PMDI content increased, the morphology of dispersed phase changed from droplet dispersion to rodlike shape and then to an irregular structure. The DSC results showed that the crystallinity of PET decreased in the presence of PMDI, and the glass transition temperature ( T g) of PET increased with addition of 0–0.7 w% PMDI. The impact strength of the blend with 1.1 w% PMDI increased by 120% with respect to the blend without PMDI, accompanied by only an 8% tensile strength decrease. It was demonstrated that the chain extension of PET with PMDI in R-PET/LLDPE/SEBS- g-MA blends not only decreased the compatibilization effect of SEBS- g-MA but also hindered the crystallization of PET.

Preparation of Functional Polystyrene Copolymers Through Nitroxide Mediated Polymerization and Their Applications as Surface Modifiers for BaTiO<SUB>3</SUB> Nanoparticles

Polystyrene copolymers containing maleic anhydride or maleic acid functional groups with controlled architectures were prepared through nitroxide mediated polymerization and applied to BaTiO3 nanoparticles as polymeric surface modifiers. Effective surface modification effect of BaTiO3 nanoparticles with the copolymers were observed, as evidenced by TGA, SEM, EDX and FT-IR. Modified BaTiO3 nanoparticles exhibited improved dispersion in toluene, suggesting that the amphiphilic copolymers acted as dispersants. Through the addition of the surface modifier, the viscosity of the BaTiO3/epoxy pastes decreased and the dielectric constants of the resulting nanocomposite films increased. Molecular weight and number of functional groups of the copolymers were important factors to ascertain good processability and high dielectric constants of the composite.

Preparation and nonisothermal crystallization behavior of polypropylene/layered double hydroxide nanocomposites

Polypropylene (PP)/layered double hydroxide (LDH) nanocomposites were prepared via melt intercalation using dodecyl sulfate anion modified LDH and maleated PP as compatibilizing agent. Evidently the interlayer anions in LDH galleries react with maleic anhydride groups of PP-g-MA and lead to a finer dispersion of individual LDH layers in the PP matrix. The nanostructure was characterized by XRD and TEM; the examinations confirmed the nanocomposite formation with exfoliated/intercalated layered double hydroxides well distributed in the PP matrix. The nonisothermal crystallization behavior of resulting nanocomposites was extensively studied using differential scanning calorimetry (DSC) technique at various cooling rates. In nonisothermal crystallization kinetics, the Ozawa approach failed to describe the crystallization behavior of nanocomposites, whereas the Avrami analysis and Jeziorny method well define the crystallization behavior of PP/LDH nanocomposite. Combined Avrami and Ozawa analysis (Liu model) also found useful. The results revealed that very small amounts of LDH (1%) could accelerate the crystallization process relative to the pure PP and increase in the crystallization rates was attributed to the nucleating effect of the nanoparticles. Polarized optical microscopy (POM) observations also support the DSC results. The effective crystallization activation energy was estimated as a function of the relative degree of crystallinity using the isoconversional analysis. Overall, results indicated that the LDH particles in nanometer size might act as nucleating agent and distinctly change the type of nucleation, growth and geometry of PP crystals.

Synthesis and characterization of high‐density polypropylene‐grafted polyethylene via a macromolecular reaction and its rheological behavior

AbstractHigh‐density polyethylene grafted isotactic polypropylene (PP‐g‐HDPE) was prepared by the imidization reaction between maleic anhydride grafted polyethylene and amine‐grafted polypropylene in a xylene solution. The branch density was adjusted by changes in the molar ratio between maleic anhydride and primary amine groups. Dynamic rheology tests were conducted to compare the rheological properties of linear polyolefins and long‐chain‐branched polyolefins. The effects of the density of long‐chain branches on the rheological properties were also investigated. It was found that long‐chain‐branched hybrid polyolefins had a higher storage modulus at a low frequency, a higher zero shear viscosity, a reduced phase angle, enhanced shear sensitivities, and a longer relaxation time. As the branch density was increased, the characteristics of the long‐chain‐branched structure became profounder. The flow activation energy of PP‐g‐HDPE was lower than that of neat maleic anhydride grafted polypropylene (PP‐g‐MAH) because of the lower flow activation energy of maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MAH). However, the flow activation energy of PP‐g‐HDPE was higher than that of PP‐g‐MAH/HDPE‐g‐MAH blends because of the presence of long‐chain branches. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Cellulose/polypropylene composites: Influence of the molecular weight and concentration of oxidatively degraded and maleated polypropylene compatibilizers on tensile behavior

AbstractTo improve interactions between fibrous cellulose (FC) and polypropylene (PP), oxidatively degraded polypropylene (DgPP) and maleated polypropylene (MAPP) were studied as compatibilizers. Both compatibilizers had the same mechanism, using esterification between the OH group in FC and the reactive (γ‐lactone, acid, and maleic anhydride) groups in the compatibilizers. However, the adhesion style with the ester bond was considerably different because of the arrangements of the reactive groups. DgPP had reactive groups at the polymer chain end, and the tensile behavior of the FC/PP/DgPP composite exhibited comparatively ductile behavior. However, MAPP had inner reactive groups, and the tensile behavior of the FC/PP/MAPP composite was quite brittle. Observation of these fracture surfaces suggested that the adhesion performance of the interface between FC and PP was strongly influenced by the arrangements of the reactive group. In addition, the performance was influenced by the molecular weight of DgPP and by the content of maleic anhydride groups in MAPP. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

POLYETHYLENE TERNARY BLENDS - CLAY NANOCOMPOSITES

Nanocomposites made from a ternary blend of high, low and linear-low density polyethylene (in specific proportions) and bentonite clay nanoparticles, are studied in this work. Particular attention is given to their characterization, mechanical and rheological properties of the nanocomposites. To enhance exfoliation, dispersion and interactions of the particles with the matrix, the particles were modified with L-lysine and one of the components of the matrix (LDPE) was grafted with maleic anhydride groups. With respect to the reference ternary blend, the resulting system presents increases of 13 % in tensile strength, 140 % strain at break, 111 % strength at break, 11 % tear strength with no change in the modulus. When only modified particles are added, a drastic change of the rheological properties is observed, i.e., a lower viscosity and higher relaxation time. This latter behavior has also been observed in other nanocomposite systems.

Influence of polarity on the preferential intercalation behavior of clay in immiscible polypropylene/polystyrene blend

AbstractThe immiscible polypropylene (PP)/polystyrene (PS) blend was prepared via melt compounding and the preferential intercalation behavior of clay was investigated by wide angle X‐ray diffraction (XRD) and transmission electron microscope (TEM). It was found that the clay platelets initially located in the PS phase in PP/PS/Clay composites and PS chains intercalated into the clay layers. However, all clay migrated from the PS phase to the modified PP phase after introducing polar maleic anhydride group (MAH) to PP chains. Interestingly, most of clay migrated from the modified PP phase to the modified PS phase again when PS matrix was modified with sulfonic group, and some enriched in the interphase region. The interaction energy density (B) of the blends was determined by combining the melting point variation with the ternary interaction model for heat of mixing. It was found that the value of B decreased with the introduction of polar group (MAH or sulfonic group), indicating that the polarization of PP and PS can enhance interaction between clay platelet and polymer component. Different interaction between clay platelet and polymer component leads to the preferential intercalation behavior. The higher polarity of the polymer generates higher interaction between clay and polymer component as well as results in stronger preferential intercalating ability. Moreover, the results of FTIR spectra after extraction of all samples gave additional explanation of the preferential intercalation behavior of clay in the immiscible PP/PS blends. On the basis of the results of the measurement mentioned above, a possible mechanism was proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008