Structure-property behavior of gamma-irradiated poly(styrene) and poly(methyl methacrylate) miscible blends

The objective of this research was to investigate the miscibility behavior of urea-formaldehyde (UF) resin and vinyl acetate versatic ester copolymer latex (VAcVe) blends. Blend of various compositions of UF resin as thermoset polymer and VAcVe as thermoplastic polymer were prepared. This study shows how the addition of VAcVe latex can alter the behavior of UF resin toward hardness, press-ability, and inhibition of cracks occurred in the UF resin films and moulds. After that, these blends (UF/VAcVe) were irradiated with gamma rays in different doses. Physical properties such as solubility percent, water absorption behavior in water, and effect of dilute acid and dilute alkali were studied. Thermogravimetric analysis shows that VAcVe is more stable against thermal decomposition than UF resin over the entire temperature range studied. Also, the thermal stability of polymer blends (UF/VAcVe) increases with increasing the ratio of VAcVe component in the blend. The influence of addition of VAcVe on compressive strength was studied. The results showed an improvement with a decrease in compressive strength due to the flexibility, this improvement is related to the amount of VAcVe.

Section: Resultsmentioning

confidence: 99%

The use of gamma irradiation to induce the miscibility between urea‐formaldehyde and vinyl acetate versatic ester copolymer latex blend

Taha

Magida

Shehata

2012

“…On the other hand, the thermal stability of unirradiated S‐VAc/NRL blends at any composition is higher than those of pure components, especially polymer blends rich in S‐VAc content on the basis of percent weight loss. This is because rubber thermoplastic blends possess a combination of physical and rheological properties that are unavailable in a single polymer 3–5. Moreover, NRL is highly unsaturated and the double bonds remaining in the monomeric unit (polyisoprene) after polymerization are susceptible to degradation by heating.…”

Section: Resultsmentioning

confidence: 99%

“…While the used rubber or elastomeric copolymer has decisive influence on elastic properties of PSA, the low molecular tackifier resins or tacky admixtures significantly influence the viscoelastic properties of PSA and its ability to wet the surface of adherent 2. Moreover, certain rubbery thermoplastic blends possess a combination of physical and rheological properties that are unavailable in a single polymer 3. PSA are made by irradiating an uncured mixture of polymerizable compounds either by ultraviolet light or by electron beam (EB) to form a polymeric film of an adhesive.…”

Section: Introductionmentioning

confidence: 99%

The use of compatible blend of styrene‐vinylacetate copolymer/natural rubber latex in pressure‐sensitive adhesive applications by using irradiation and chemical initiation

Magida

Gad

El‐Nahas

2009

Thermoplastic elastomers from blends of styrene‐vinylacetate copolymer latex (S‐VAc) and natural rubber latex (NRL) as a hydrophilic/hydrophobic blend have been prepared by the solution‐casting technique. Compatibility between S‐VAc and NRL was confirmed at all ratios of the blend mixing through the measurements of water absorption, thermogravimetric analysis, and scanning electron microscope. The prepared blend was studied for pressure‐sensitive adhesive (PSA) application. Nonylphenol ethoxylate (NPE) was used as a chemical tackifier to initiate a sticky property for S‐VAc. Also, electron beam irradiation was applied as a physical tackifying agent to promote stickiness for NRL at 12.5 Mrad or at 2.5 Mrad by addition of NPE tackifier. Peel strength, tensile strength, elongation at break, surface hardness, and aging time were investigated. Two types of double‐sided PSA were prepared: the first to be applied at room temperature; the second to be applied thermally at 80°C. The obtained PSA adhesive was suggested to be used for adhering the synthetic veneers to the particle wood panels. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

“…When Δlog ( dw / dt ) is plotted against Δlog ŵ, it gives a straight line of slope ‘ n ’ and the intercept gives the activation energy E *. The procedure and application of this method have been described elsewhere 21, 22. Figures 7 and 8 show the plots of Anderson–Freeman method, from which the activation energy can be calculated.…”

Section: Resultsmentioning

confidence: 99%

Electron beam synthesis and characterization of poly(vinyl alcohol)/montmorillonite nanocomposites

Alla

El‐Din

El‐Naggar

2006

Poly(vinyl alcohol) (PVA)/montmorillonite clay (MMT) nanocomposites in the form of films were prepared under the effect of electron beam irradiation. The PVA/MMT nanocomposites gels were characterized by Xray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and mechanical measurements. The study showed that the appropriate dose of electron beam irradiation to achieve homogeneous nanocomposites films and highest gel formation was 20 kGy. The introduction of MMT (up to 4 wt %) results in improvement in tensile strength, elongation at break, and thermal stability of the PVA matrix. In addition, the intercalation of PVA with the MMT clay leads to an impressive improved water resistance, indicating that the clay is well dispersed within the polymer matrix. Meanwhile, it was proved that the intercalation has no effect on the metal uptake capability of PVA as determined by a method based on the color measurements. XRD patterns and SEM micrographs suggest the coexistence of exfoliated intercalated MMT layers over the studied MMT contents. The DSC thermograms showed clearly that the intercalation of PVA polymer with these levels of MMT has no influence on the melting transitions; however, the glass transition temperature (T g ) for PVA was completely disappeared, even at low levels of MMT clay.