Maleic Anhydride Polyethylene Research Articles

Cellular Structure of EVA/ATH Halogen-free Flame-retardant Foams

Composites of etylene vinyl acetate (EVA)/aluminum trihydroxide (ATH) (up to 70 wt%) were foamed to create new materials with good fire retardancy properties and low weight, proving the feasibility of developing cellular structures when high levels of halogen-free flame retardants (HFFR) are included. An experimental study was carried out to explore the effects of chemical composition on cellular structure as well as the effect of structure on thermal stability, mechanical and combustion properties. Sample fabrication was carried out using an improved compression molding route consisting of polymer compounding, precursor preparation and foaming under pressure. The polymer matrix consisted of EVA as well as certain amount of linear low-density polyethylene-maleic anhydride as coupling agent. The inorganic filler used was ATH ranging from 0 wt% to 70 wt%. Furthermore, azodicarbonamide was used as chemical blowing agent. Foamed samples with cell sizes below 100 µm were produced. These samples showed similar fire retardancy than their solid precursors. The compatibilization was proved indispensable to achieve a good adhesion between mineral filler and polymer and to improve the cellular structure. The increase of the amount of filler has an interesting effect on the cellular structure, going from a closed-cell (up to 50 wt% of ATH) to an open-cell cellular structure (60 wt% of ATH or more). The feasibility of producing HFFR cellular materials has been demonstrated as a result of this investigation, leading to a notable reduction of material compared to the solid one and to new properties which can result in new applications.

Physical and Mechanical Properties of a Highly Filled Old Corrugated Container (OCC) Fiber/Polyethylene Composite

Physical and mechanical properties of a new composite of 70% (by weight) old corrugated container recycled fibers, 27% high-density polyethylene, and 3% compatibilizer (maleic anhydride polyethylene) were evaluated with a focus on dimensional stability. Maximum water absorption, thickness swelling, width swelling, and length swelling were 25, 14, 5, and 1.5%, repectively. Relationships between water absorption and dimensional swelling were established using nonlinear curve fitting and statistically significant relationships were obtained. Swelling rate constants were determined for the 3D swelling behavior of the composite material using a previously published model which showed decrease in swelling rate in width and length directions. In all directions, the swelling model satisfactorily predicted the swelling behavior. Mechanical properties of the composite material were evaluated prior to and after exposure to simulated freeze—thaw cycling and it was concluded that the cycling was ineffective on mechanical performance.

Analysis of Among-Species Variability in Wood Fiber Surface Using DRIFTS and XPS: Effects on Esterification Efficiency

Variability in the chemical composition of surface properties of various wood fibers (eastern white cedar, jack pine, black spruce, and bark) was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and X-ray photoelectron spectroscopy (XPS). Both DRIFTS and XPS showed high variability in fiber surface composition between species and between fiber types (sapwood, heartwood, and bark). Fiber surface was modified by esterification reaction using a maleic anhydride polyethylene (MAPE) treatment. DRIFTS failed to assess surface modification, whereas XPS results showed that MAPE treatment increased the surface hydrocarbon concentration of jack pine wood fiber, indicated by a decrease in oxygen–carbon ratio and an increase in relative intensity of the C1 component in the C1s signal. Lignin concentration variability on the fiber surface was determined as the major factor that prevents esterification from taking place.

Physical Properties of Novel Layered Composites of Wood Flour and PVC

Various formulations of wood flour and rigid Poly Vinyl Chloride (PVC) composites were prepared and the effects of layering and composite composition on their physical properties were studied. Beech wood flour, PVC, Maleic Anhydride Polyethylene (MAPE), and beech veneer were used to produce the composites in a two-step conventional hot press system. Physical property tests, including equilibrium moisture content (EMC), long term water absorption and thickness swelling were carried out. The results indicated that, by the increase in PVC content from 20% to 30%, EMC, maximum water absorption and maximum thickness swelling decreased. No significant relationship was observed between PVC content and water diffusion coefficient, whereas layered composites on average had higher water diffusion coefficients in comparison with unlayered composites. Results of laminating revealed that it caused a decrease in the EMC, and an increase in maximum water absorption and maximum thickness swelling.

Effects of Accelerated Freeze—Thaw Cycling on Physical and Mechanical Properties of Wood Flour/PVC Composites

Various formulations of wood flour and rigid polyvinyl chloride (PVC) composites were prepared and the effects of three accelerated freeze—thaw cycles on their physical and mechanical properties were studied according to ASTM D7031 specification. Beech (Fagus orientalis) wood flour, PVC, maleic anhydride polyethylene (MAPE), and beech veneer were used to produce the composites in a two-step conventional hot press system. A thickness swelling test was carried out as an indicator of physical property. Mechanical characteristics of composites were evaluated after each cycle using three-point flexural tests, and losses in mechanical properties were studied. Results indicated that thickness swelling was not affected by freeze—thaw cycling while significant relationship was observed between PVC content and thickness swelling and with increase in PVC content, maximum thickness swelling decreased. The values of flexural strength (MOR) and modulus (MOE), were significantly affected by PVC content, layer, and freeze—thaw cycling. Layering of the specimens and higher PVC contents improved MOR and MOE while freeze—thaw cycling decreased them at the first cycle. Repeated freeze—thaw cycling did not exhibit a significant effect on the mechanical properties and the effect of the cycles was confined to the first cycle only. Increase of PVC content had positive effect on both physical and mechanical properties.

Effect of compatibilizer on the natural durability of wood flour/high density polyethylene composites against rainbow fungus (Coriolus versicolor)

AbstractTo evaluate the effect of compatibilizer on the natural durability of wood flour/high density polyethylene composites against Coriolus versicolor, composites containing 25% and 50% by weight maple wood flour and 1% and 2% compatibilizer (Maleic anhydride polyethylene (MAPE)), respectively, were sampled. Identical specimens of the same composites without the compatibilizer were also prepared. Physical and mechanical properties of all specimens, including water absorption, flexural modulus, flexural strength, impact strength and hardness, were determined prior to and after incubation with the fungus for 14 weeks at 25°C and 75% relative humidity. Weight losses of the specimens were also determined after incubation. Results indicated that the compatibilizer had significant effects on the natural durability of the studied composite formulations so that all mechanical properties were affected by the fungus to greater extents in the case of uncompatibilized specimens than the compatibilized ones. Weight loss of the uncompatibilized composites was also higher than that of compatibilized ones. Higher water absorption was observed in all cases after incubation. However, the increase in water absorption was considerably higher in the case of uncompatibilized specimens. POLYM. COMPOS., 28:273–277, 2007. © 2007 Society of Plastics Engineers

Maleic Anhydride Polyethylene Octene Elastomer Toughened Polyamide 6/Polypropylene Nanocomposites: Mechanical and Morphological Properties

AbstractA series of polyamide 6/polypropylene (PA6/PP) blends and nanocomposites containing 4 wt% of organophilic modified montmorillonite (MMT) were designed and prepared by melt compounding followed by injection molding. Maleic anhydride polyethylene octene elastomer (POEgMAH) was used as impact modifier as well as compatibilizer in the blend system. Three weight ratios of PA6/PP blends were prepared i.e. 80:20, 70:30, and 60:40. The mechanical properties of PA6/PP blends and nanocomposite were studied through flexural and impact properties. Scanning electron microscopy (SEM) was used to study the microstructure. The incorporation of 10 wt% POEgMAH into PA6/PP blends significantly increased the toughness with a corresponding reduction in strength and stiffness. However, on further addition of 4 wt% organoclay, the strength and modulus increased but with a sacrifice in impact strength. It was also found that the mechanical properties are a function of blend ratio with 70:30 PA6/PP having the highest impact strength, both for blends and nanocomposites. The morphological study revealed that within the blend ratio studied, the higher the PA6 content, the finer were the POEgMAH particles.

A cyclic peptide–polymer probe for the detection of Clostridium botulinum neurotoxin serotype A

A Botulinum neurotoxin serotype A (BoNT/A) ELISA detection system was developed based upon an 11-mer cyclic peptide, termed C11-019, that was identified through peptide phage display technology. The assay employs a sandwich format using the C11-019 cyclic peptide attached to a PEMA (poly(ethylene maleic anhydride)) matrix as the capture phase and anti-BoNT/A polyclonal antibodies as the detection phase. Results reported demonstrate that the C11-019 peptide–polymer can specifically bind to BoNT/A with no cross-reactivity to other serotypes examined in assay buffers and a variety of body fluids and foodstuffs. When a highly sensitive chemiluminescent substrate was engaged, the detection of 1 pg/mL could be readily achieved within 3 h with a linear range of 0.1–1 ng/mL. These results demonstrate that an inexpensive peptide–polymer-based capture ELISA system can be used for rapid, sensitive and highly specific BoNT detection.

Effect of Premade Compatibilizer and Reactive Polymers on Polystyrene Drop Deformation and Breakup in Simple Shear

The deformation and breakup of a single polymer drop with compatibilizer (premade or in-situ) inside a polymer matrix was visualized at high temperature under simple shear in a specially designed transparent Couette mixer. The compatibilized systems were polyethylene/polystyrene (PE/PS) with polyethylene-block-polystyrene copolymer (P(E-b-S)) and polystyrene oxazoline (PSOX) with polyethylene maleic anhydride (PEMA). The uncompatibilized polymer systems studied were PE/PS and PE/PSOX. With or without compatibilizer, the drop elongated in the vorticity direction and then broke up in that direction. In the presence of premade or reactively formed compatibilizer, drop breakup occurs at a shear rate similar to that in the uncompatibilized systems, which suggests that copolymer does not affect initial polymer drop breakup greatly. Interfacial cross-linking in reactive systems stabilized the drop by forming a tiny cylindrical tip in the vorticity direction. Consequently, drop erosion and vorticity elongation and breakup occurred at a much higher shear rate compared to the nonreactive systems.

Effect of mape on the mechanical properties of rubber wood fiber/thermoplastic natural rubber composites

AbstractRubber wood fiber/reinforced thermoplastic natural rubber (RWF/TPNR) composites were prepared. A blend of natural rubber with high‐density polyethylene was prepared by melt blending the materials in the internal mixer of Brabender Plasticorder machine. RWF and TPNR were mixed with different fractions of fiber (0, 5, 10, 20, and 30%) in the internal mixer. To investigate the influence of coupling agent on the mechanical properties, concentrations of maleic anhydride polyethylene (MAPE) were employed in the composites. The mechanical properties and morphology of composite material were characterized with tensile machine and scanning electron microscope, respectively. The results showed that the addition of MAPE has a positive effect on the tensile strength and Young's modulus while the maximum strain was reduced. SEM micrographs showed good adhesion between RWF and TPNR when the coupling agent was applied. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 18–23, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10070