A Study of the Synthesis of EPDM-g-MAN and Toughness of its Blend with SAN (AEMS)

Ethylene–propylene–diene–methyl methacrylate/acrylonitrile terpolymers (EPDM-g-MAN) were synthesized by comonomers methyl methacrylate and acrylonitrile (MMA-AN) grafted on EPDM macromolecules with solution graft copolymerization. The engineering plastics of the blend of EPDM-g-MAN with SAN (AEMS) were prepared by blending EPDM-g-MAN with SAN resin. The effect of AN/MMA-AN weight percentage (f _AN) on monomer conversion ratio, grafting ratio, and grafting efficiency of the graft copolymerization and the notched Izod impact strength of AEMS were investigated. The notched Izod impact strength of AEMS, prepared by blending SAN with EPDM-g-MAN, was synthesized under our optimum S2 reaction conditions, with EPDM/MMA-AN weight proportion of 50/50 and f _AN of 10 wt%, presenting a peak with the maximum value of 61.0 kJ/m². The microstructure of AEMS prepared with S2 reaction conditions showed that when the polarity of EPDM-g-MAN was appropriate, the EPDM phase formed a pseudocontinuous phase in the SAN matrix and the interfacial adhesion was strong, which could induce shear yielding of the SAN matrix. Differential scanning calorimetry analysis showed that there was good compatibility between SAN resin and EPDM-g-MAN synthesized with f _AN of 10 wt% and a EPDM/MMA-AN weight ratio of 50/50.     

Effect of Unplasticized Poly Vinyl Chloride (UPVC) Molecular Weight and Graft-Acrylonitrile-Butadiene-Styrene (g-ABS) Content on Compatibility and Izod Impact Strength of UPVC/g-ABS Blends

In this study three grades of rigid poly vinyl chloride (PVC) having different molar masses were melt blended with graft-acrylonitrile-butadiene-styrene (g-ABS) in different compositions. The effect of PVC molecular weight and g-ABS composition on the compatibility and Izod impact strength of the blends were investigated. Differential scanning calorimetry (DSC) results showed a single glass transition temperature (T_g) for all the blends, representative of miscibility between the PVC phase and the styrene-acrylonitrile copolymer (SAN) phase of g-ABS which, in turn, led to compatibility of the PVC/g-ABS blends. It was observed that in all the PVC grades the blends Izod impact strength increased with increasing g-ABS content. Also, at a given composition of g-ABS, by increasing the molecular weight of the PVC phase the impact strength of the blends increased. The morphology of the fracture surfaces from the impact tests were analyzed using scanning electron microscopy (SEM) micrographs and the results showed that with increasing g-ABS content in the blend, cloudy regions increased and eventually begin to overlap each other, and the deformed material on the fracture surfaces increased. This was attributed to the blend compatibility causing greater energy dissipation in the fracture process.     

Reactive Compatibilization of Poly(trimethylene terephthalate)/Polypropylene Blends by Polypropylene‐graft‐Maleic Anhydride. Part 1. Rheology,Morphology, Melting,and Mechanical Properties

Poly(trimethylene terephthalate)/polypropylene (PTT/PP) blends were prepared by melt blending. The rheology, morphology, melting, and mechanical properties of PTT/PP blends were investigated with and without the addition of polypropylene‐graft‐maleic anhydride (PP‐g‐MAH). The melt viscosity results showed that the fluid behavior of PTT/PP blends exhibited great disparity to that of PTT but similar to that of PP; the dispersed flexible PP phase in the blends served as a “ball bearing effect” under shear stress, which made the fluid resistance markedly reduced; by contrast, the relatively rigid PTT dispersed phase made only a small contribution to the viscosity. With 5 wt.% PP‐g‐MAH addition during melt processing, both the shear viscosity and the non‐Newtonian index of 70/30 PTT/PP blend were increased over that of the corresponding uncompatibilized one, whereas the shear viscosity of the 30/70 PTT/PP melt decreased slightly indicating that a considerable amount of PP‐g‐MAH did not act as compatibilizer but probably served as plasticizer.

With the increasing of the other component, the melting temperature of the PTT phase showed a slight decrease while the melting temperature of the PP phase showed a slight increase. 5 wt.% PP‐g‐MAH addition had little influence on the melting temperatures of the two components. When PP≤20 wt.%, the cold crystallization temperature of the PTT phase (T_cc (PTT‐phase)) showed little change with the composition; however, it shifted to higher temperature when PP≥30 wt.%. The variations of the T_cc (PTT‐phase), with and without PP‐g‐MAH, suggested that, when PTT was a minor component, the excess PP‐g‐MAH which did not act as compatibilizer might serve as a plasticizer that made the PTT's cold crystallization process to be easier. The SEM results indicated that, for the uncompatibilized blends, the interfaces from particles pulling‐out are clear and smooth, while, for compatibilized blends, the reactive products are at the interfaces. The mechanical properties suggested that PP‐g‐MAH did not result in significant improvement of the toughness of the blend, but the tensile strength increased markedly.     

Effect of Poly(butyl acrylate)-g-poly(styrene-co-acrylonitrile)’s Core/shell Ratio on Mechanical and Thermal Properties of Poly(butyl acrylate)-g-poly(styrene-co-acrylonitrile)/α-methylstyrene-acrylonitrile Binary Blends

Poly(butyl acrylate)-g-poly(styrene-co-acrylonitrile) terpolymer (PBA-g-SAN) with different core/shell ratios and α-methylstyrene-acrylonitrile (α-MSAN) were mixed via melt blending (25/75, W/W). It was found that the core/shell ratio of PBA-g-SAN played an important role in the toughening of rigid α-MSAN. According to an analysis of the impact strength and the morphologies of the impact fractured surfaces, the optimum core/shell ratio with the highest toughening efficiency was 60/40. Considering the results of dynamic mechanical thermal analysis (DMTA), the blends retained the high glass transition temperature (T_g) of α-MSAN because of the immiscibility between the two components. Moreover, increasing the core/shell ratio did not result in sacrificing the heat distortion temperature of the blends, which was attributed to the almost unchanged high temperature T_g of α-MSAN. The tensile strength, flexural strength, and modulus declined slightly with the increasing core content of PBA-g-SAN, which suggested that the stiffness of the blends decreased with the increasing core/shell ratio. This study showed that 60/40 was the optimum core/shell ratio used for toughening modification; it achieved a good balance between mechanical and heat resistance performance.     

Formation of β-iPP in Isotactic Polypropylene/Acrylonitrile–Butadiene–Styrene Blends: Effect of Resin Type,Phase Composition,and Thermal Condition

The formation of β-iPP (β-modification of isotactic polypropylene) in the iPP/ABS (acrylonitrile–butadiene–styrene), iPP/styrene–butadiene (K resin), and iPP/styrene–acrylonitrile (SAN) blends were studied using differential scanning calorimery (DSC), wide angle X-ray diffraction (WAXD), and scanning electron microscopy (SEM). It was found that α-iPP (α-modification of isotactic polypropylene) and β-iPP can simultaneously form in the iPP/ABS blend, whereas only α-iPP exists in the iPP/K resin and iPP/SAN blend samples. The effects of phase composition and thermal conditions on the β-iPP formation in the iPP/ABS blends were also investigated. The results showed that when the ABS content was low, the ABS dispersed phase distributed in the iPP continuous phase, facilitating the growth of β-iPP, and the maximum amount of β-iPP occurred when the composition of iPP/ABS blend approached 80:20 by weight. Furthermore, it was found that the iPP/ABS blend showed an upper critical temperature T _c * at 130°C for the formation of β-iPP. When the crystallization temperature was higher than the T _c *, the β-iPP did not form. Interestingly, the iPP/ABS blend did not demonstrate the lower critical temperature T _c ** previously reported for pure iPP and its blends. Even if the crystallization temperature decreased to 90°C, there was still β-iPP generation, indicating that ABS has a strong ability to induce the β-iPP. However, the annealing experiments results revealed that annealing in the melt state could eliminate the susceptibility to β-crystallization of iPP.     

Isothermal Melt Crystallization Kinetics for Poly(Trimethylene Terephthalate)/Poly(Butylene Terephthalate) Blends

The kinetics of isothermal melt crystallization of poly(trimethylene terephthalate) (PTT)/poly(butylene terephthalate) (PBT) blends were investigated using differential scanning calorimetry (DSC) over the crystallization temperature range of 184–192°C. Analysis of the data was carried out based on the Avrami equation. The values of the exponent found for all samples were between 2.0 and 3.0. The results indicated that the crystallization process tends to be two‐dimensional growth, which was consistent with the result of polarizing light microscopy (PLM). The activation energies were also determined by the Arrhenius equation for isothermal crystallization. The values of ΔE of PTT/PBT blends were greater than those for PTT and PBT. Lastly, using values of transport parameters common to many polymers (U*=6280 J/mol, T _∞=T _g – 30), together with experimentally determined values of T _m ⁰ and T _g, the nucleation parameter, K _g, for PTT, PBT, and PTT/PBT blends was estimated based on the Lauritzen–Hoffman theory.     

Solution blends of polyacrylonitrile with segmented polyurethanes: Effect of soft segments

Solution blends of a modified polyacrylonitrile (PAN) with polyurethane (PU) obtained from 4, 4′-diphenylmethane diisocyanate (MDI) and two different types of polyols– i.e., ether-linked polytetramethylene ether glycol (PTEG) and ester-linked polytetramethylene adipate glycol (PTAG) – were prepared in N, N-dimethylformamide (DMF). The domains in the PTAG-PU blends were much finer than those in the PTEG-PU blends. Shift of the soft segment transition temperatures (T _gs) of PU toward lower temperature with increasing PAN was more significant for PTAG-PU blends. Miscibility was also examined through Fourier transform infrared spectra. These showed clear carbonyl peak shifts due to the different types of hydrogen bonding. The PTAG-PU/PAN (30/70) blend had the maximum draw ratio at failure, measured in 100°C water; it was over 2.5 times that of pure PAN.     

The Shear‐Dependent Phase Separation Behavior of the Ternary Blend Polystyrene/Polyvinyl Methyl Ether/Styrene–Acrylonitrile Copolymer

The phase behavior and phase separation dynamics of a PS/PVME/SAN ternary blend using light scattering under a shear rate range of 0.1～40 s^?1 were investigated. The cloud point temperature first increases and then decreases with the increase of shear rates. At higher shear rates, the cloud point temperature again increases. The phase separation behavior in the early and later stages under shear field can be explained by the Cahn–Hilliard theory and the exponential growth law, respectively. The delay time τ _d ?, the apparent diffusion coefficient D _app, the growth rate R(q), and the exponent term show strong dependence on the difference between the experimental temperature and the cloud point temperature (ΔT), and on the shear rates. Compared with PS/PVME binary blends at lower shear rates, τ _d for a PS/PVME/SAN ternary blend is smaller, while at higher shear rates τ _d is larger. At higher shear rates, the introduction of the third component SAN to a PS/PVME binary blends slows the phase separation process.     

Toughening Effect of Ethylene Propylene DieneTerpolymer-Graft-Styrene-Acrylonitrile Copolymer (EPDM-g-SAN) on SAN Resin

The reaction product EPDM-g-SAN, synthesized by suspension graft copolymerization of styrene (St) and acrylonitrile (AN) in the presence of ethylene-propylene-diene terpolymer (EPDM), was blended with a commercial styrene-acrylonitrile copolymer (SAN resin) to prepare AES blends with high impact strength. The effects of AN mass percentage in the St-AN comonomer mixture (f _AN), EPDM mass percentage in the feed of EPDM and St-AN (f _EPDM) and reaction time on monomer conversion ratio (CR), grafting ratio (GR), and AES notched Izod impact strength were characterized. The notched Izod impact strength of AES containing 15 wt% EPDM reached its maximum with f _AN of 40 wt% and f _EPDM of 45 wt%; this was attributed to the polarity of the SAN copolymer obtained being appropriate with that of the SAN resin matrix. The dependences of GR and the notched Izod impact strength of AES containing 25 wt% EPDM on the reaction time were in rough agreement. The effect of EPDM content on the AES notched Izod impact strength indicated that the brittle-ductile transition of AES occurred for an EPDM content from 12.5 to 15 wt%. TEM and SEM analysis showed that the phase structure of AES exhibited a “salami” like structure, and the toughening mechanism of AES was shear yielding of the SAN resin matrix, which endowed AES with excellent toughness.     

Toughening Effect of Poly(ethene-co-1-butene)-graft-methyl Methacrylate and Acrylonitrile on Styrene-acrylonitrile Copolymer (SAN)

Poly(ethene-co-1-butene)-graft-methyl methacrylate-acrylonitrile (PEB-g-MAN), synthesized by suspension grafting copolymerization of methyl methacrylate and acrylonitrile onto PEB, was blended with styrene-acrylonitrile copolymer (SAN). The mechanical properties, phase structure, toughening mechanism, miscibility, and thermal stability of the SAN/PEB-g-MAN blends were studied using a pendulum impact tester, tension tester, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TG). The results showed that PEB-g-MAN has an excellent toughening effect on SAN resin. The notched impact strength of the blends (containing 25 wt% PEB) was 63.3 kJ/m², which was nearly 60 times that of SAN resin. The brittle-ductile transition of SAN/PEB-g-MAN blends occurred when the weight percentage of PEB was between 17.5 and ～20 wt%. SAN and PEB-g-MAN were partially miscible. The toughening mechanism of the blends changed with the PEB content. When the PEB content was low, the toughening mechanism of the blends was branching and termination of cracks with slight cavitation. As the content of PEB increased, the toughing mechanism gradually changed from branching and termination of crack with slight cavitation to both branching and termination of crack and cavitation, to extensive cavitation, and finally to shear yielding accompanied by cavitation. The phase structure of the blends changed from a “sea-island’’ structure to a cocontinuous structure as the PEB content increased. ATG analysis showed that the thermal properties of the SAN resin in the blends were enhanced by adding the PEB-g-MAN.     

Microhardness of condensation polymers and copolymers. 1. Coreactive blends of polyethylene terephthalate and polycarbonates

The microhardness of coreactive blends of polyethylene terephthalate (PET) and bisphenol A polycarbonate (PC) was investigated over the whole range of compositions. The occurrence of one single glass transition temperature (T _g) step in the differential scanning calorimetry (DSC) curves indicated that intensive chemical interactions had taken place during melt blending, resulting in formation of copolycondensates with dominating random sequential order. The parallel decrease of microhardness (H) and of T_g with increasing PET content in the blends has been ascribed to the formation of new copolymer molecules enriched in the component characterized by lower H and T _g values. It is emphasized that such noncrystallizable copolymers offer the possibility to evaluate the intrinsic contribution of the repeating units to the H and T _g characteristics of copolymers with various compositions and sequential orders.     

Preparation and Characterization of Two Types of Cyanate Ester-epoxy Resin Interpenetrating Network Matrix/Butadiene-acrylonitrile Rubber Composites

Two types of butadiene-acrylonitrile rubbers (i.e., carboxyl randomized butadiene-acrylonitrile rubber (CRBN) and hydroxyl terminated butadiene-acrylonitrile rubber (HTBN)) have been used for modifying an interpenetrating network of cyanate ester (CE)/epoxy resin (EP) (70/30). The toughness of the matrix can be improved effectively with addition of rubbers. The values of impact strength (11.6 KJ/m²) show a maximum for the CE/EP/HTBN (70/30/8) blend. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results show that CRBN and HTBN have a different dispersion state in the CE/EP matrix. CRBN aggregates to form regular spheres with a size of about 1 μm. HTBN disperse homogeneously with its size of the nano-level (about 10 nm). Fourier transform infrared spectrum (FTIR) and differential scanning calorimetric (DSC) analysis shows that the CRBN has higher reactivity than HTBN. The thermal gravimetric analysis (TGA) results shows that T ₁₀ (temperature of 10% weight loss) of the CE/EP system decreases with the addition of rubbers. For the CE/EP/CRBN system, both T ₃₀ (temperature of 30% weight loss) and T ₅₀ (temperature of 50% weight loss) are lower than neat CE/EP. However, for the CE/EP/HTBN system, both T ₃₀ and T ₅₀ are near to neat CE/EP. Different reactivity and compatibility between the rubbers and CE/EP matrix is the main determining factor for the thermal stability of the blends.     

Dynamic Rheological Behavior of HDPE/UHMWPE Blends

The rheological behaviors of high-density polyethylene (HDPE)/ultra-high molecular weight polyethylene (UHMWPE) blends prepared by melt blending and solution blending were studied. The results showed that the rheological parameters (G′, G ^″, and η*) of both types of blends increased gradually with increasing fraction of UHMWPE, while the tanδ decreased correspondingly. Comparing blends with the same UHMWPE content, all G′, G ^″, and η* values of solution blends were higher, and the tanδ of the solution blends were remarkably lower than those of the melt blends. Combined with the scanning electron microscopy (SEM) observations, it was proved that, because of its very high melt viscosity, the UHMWPE chain is difficult to diffuse and be distributed well in the HDPE matrix by melt blending, resulting in a two-phase-like morphology. On the other hand, the blends prepared by the solution blending showed a homogeneous distribution of UHMWPE in the HDPE matrix. In addition, the state of aggregation of the UHMWPE in the HDPE matrix can be distinguished well by time–temperature superposition (TTS) curves; i.e., the two-phase-like morphology in the melt blends can be detected by the failure of TTS in the high-frequency range, which cannot be reflected by Cole–Cole plots and Han curves.     

Effect of Maleated Styrene/Ethylene-co-Butylene/Styrene on the Dispersed Particles Size and Mechanical Properties of Polyamide 6/Poly(styrene-co-acrylonitrile)/Poly(styrene-b-(ethylene-co-butylene)-b-styrene) Ternary Blends

In this study, the effect of several parameters, including composition, order of mixing, viscosity, and interfacial tension, on the phase structure and size of dispersed particles of polyamide 6 (PA6)/poly(styrene-co-acrylonitrile) SAN/poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) ternary blends was investigated. Moreover, the effect of addition of different ratios of reactive SEBS (maleic anhydride grafted-SEBS) and non-reactive SEBS at a fixed order of mixing and composition of 70/15/15 (PA6/SAN/SEBS + SEBS-g-MAH) on the mechanical properties of ternary blends was examined. Scanning electron microscopy (SEM) micrographs showed that among the studied parameters, interfacial tension and viscosity of dispersed phases were the leading factors in the formation of morphology and size of dispersed droplets. Mechanical results revealed that in contrast to the expectation, formation of core/shell structure of PA6/SAN/SEBS ternary blends did not result in a significant increasing of impact strength. The highest impact strength was achieved when a 50/50 weight ratio of SEBS/SEBS-g-MAH was used.     

Reactive Compatibilization of Poly(trimethylene terephthalate)/Polypropylene Blends by Polypropylene‐graft‐Maleic Anhydride. Part 2. Crystallization Behavior

The crystallization behavior of uncompatibilized and reactive compatibilized poly(trimethylene terephthalate)/polypropylene (PTT/PP) blends was investigated. In both blends, PTT and PP crystallization rates were accelerated by the presence of each other, especially at low concentrations. When PP content in the uncompatibilized blends was increased to 50–60 wt%, PTT showed fractionated crystallization; a small PTT crystallization exotherm appeared at ～135°C besides the normal ～175°C exotherm. Above 70 wt% PP, PTT crystallization exotherms disappeared. In contrast, PP in the blends showed crystallization exotherms at 113–121°C for all compositions. When a maleic anhydride‐grafted PP (PP‐g‐MAH) was added as a reactive compatibilizer, the crystallization temperatures (T _c ) of PTT and PP shifted significantly to lower temperatures. The shift of PTT's T _c was larger than that of the PP, suggesting that addition of the PP‐g‐MAH had a larger effect on PTT's crystallization than on PP due to reaction between maleic anhydride and PTT.

The nonisothermal crystallization kinetics was analyzed by a modified Avrami equation. The results confirmed that PTT's and PP's crystallization was accelerated by the presence of each other and the effect varied with blend compositions. When the PP content increased from 0 to 60 wt%, PTT's Avrami exponent n decreased from 4.35 to 3.01; nucleation changed from a thermal to an athermal mode with three‐dimensional growths. In contrast, when the PTT content increased from 0 to 90 wt% in the blends, changes in PP's n values indicated that nucleation changed from a thermal (0–50 wt% PTT) to athermal (60–70 wt% PTT) mode, and then back to a thermal (80–90 wt% PTT) mode. When PP‐g‐MAH was added as a compatibilizer, the crystallization process shifted considerably to lower temperatures and it took a longer crystallization time to reach a given crystallinity compared to the uncompatibilized blends.     

Thermal Behaviors of Confined Triphenylmethyl Chloride Crystals in Various Molecular Weight Polystyrene

The thermal behaviors of polystyrene (PS)/triphenylmethyl chloride (TPCM) blends with different polymer molecular weights were investigated through differential scanning colorimetry (DSC). It was shown that when solvent content was lower than a critical composition, there was only a single amorphous phase in the blends. With increasing polymer concentration, both T_g and T_m could be detected in DSC curves, revealing that the blends were heterogeneous. The constant T_g of the amorphous phase indicated that the composition of the amorphous phase in the blends did not depend on the solvent concentration, and the T_m depression with decreasing PS content showed the decrease of TPCM crystallite size owing to geometric constraint by the polymer chains. On the basis of the Flory–Huggins theory, the interaction parameters between PS and TPCM in the blends were obtained; they showed that the PS/TPCM blends were not thermodynamically miscible with low polymer content. The Hoffmann-Weeks equation indicated that the crystals corresponding to the lower melting point were unstable. The unstable crystals in the blends were located in the interfacial regions between the crystalline solvent molecules and the amorphous phase. The heat capacity of the blends confirmed the geometric constraint on the crystallization of TPCM in the blends.     

Activation Energy for the Glass Transition of a Confined Elastomer in HDPE/PP Blends

Blends of two highly crystalline polymers containing an elastomer were prepared to study the glass transition of the confined elastomer. The polymers chosen were high density poly ethylene (HDPE), polypropylene (PP), and two elastomers of a different nature: natural number (NR) and EPDM. The dynamic mechanical analyzer (DMA) technique was used to analyze the storage modulus of blends with elastomer content from 0% to 30% by weight, with the remainder made up of equal amounts of HDPE and PP, and blends with 10% of the elastomer, but varied ratios of polyolefins. We used the differentiation modification of the Arrhenius method in the kinetic analysis assuming an n‐order relaxation mechanism, which allowed detecting the percolation threshold of NR. Results indicate that both temperature and activation energy for glass transition (T _g ) are dependent on the types of polymers in the blend and blend composition. The T _g and E values of the unblended elastomers are higher than those in blends; this behavior is associated with the elastomer confinement and blend morphology.     

Rheological Behaviors of Polypropylene/Poly(1-butene) Blends

The rheological behaviors of polypropylene (PP)/poly(1-butene) (PB) blends with homo-polypropylene (PP₁) or impact polypropylene (PP₂), a poly(propylene-co-ethylene) as the PP component were studied. With increasing of PB resin content for both PP/PB blends, the blends showed higher G'(ω), G''(ω) and η*(ω) at low frequencies but lower values at high frequencies which implied that the processability was improved. A two-phase morphology was observed through the various rheological responses, including G'(ω)-ω terminal region curves, Cole-Cole plots and the weighted relaxation spectra with the PB contents up to 40?wt%. With the same PB content, the rheological parameters of the PP₂/PB blends were quite different from those of the PP₁/PB, which can be attributed to the stronger interaction between PB chains and the ethylene-co-propylene copolymer in PP₂. The impact strength of the PP₂/PB blends was improved dramatically over that of the PP₁/PB. The more significant toughening effect for the PP₂/PB blends can be attributed to the special responses of its rheological behaviors.     

Composite coatings of polyamide/graphene: microstructure,mechanical, thermal,and barrier properties

This effort reports on novel fluorinated polyamide (FPA) and polyamide 1010 (PA1010)-based blends and graphene reinforced nanocomposite. PA1010/FPA (80:20) blend was opted as matrix material on the basis of molecular weight, thermal, and shear stress performance. Graphene was obtained through in situ chemical method of graphene oxide reduction. PA1010/FPA/Graphene nanocomposites was developed using various graphene loadings (up to 5 wt.%). Thin film coatings were prepared on glass substrate. Consequently, the PA1010/FPA/Graphene attained regular spongy morphological pattern. PA1010/FPA/Graphene 3 also showed improved T₀ and T_max of 534 and 591 °C relative to the neat blend (T₁₀ 423 °C; T_max 551 °C). Limiting oxygen index measurement indicated better non-flammability of PA1010/FPA/Graphene 1–3 nanocomposite series (57–60%) relative to the blend series (28–31%). UL94 tests also showed V-0 rating for nanocomposites. Furthermore, PA1010/FPA/Graphene 3 nanocomposite revealed significantly high tensile strength (62 MPa), flexural modulus (1690 MPa), and adhesive properties to be utilized as coating materials. The nanocomposite coatings also displayed outstanding barrier properties against O₂ and H₂O compared with neat blends.     

Thermal behavior of gamma-irradiated low-density polyethylene/paraffin wax blend

The thermal properties of low-density polyethylene (LDPE)/paraffin wax blends were studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and melt flow index (MFI). Blends of LDPE/wax in ratios of 100/0, 98/2, 96/4, 94/6, 92/8, 90/10 and 85/15 (w/w) were prepared by melt-mixing at the temperature of 150°C. It was found that increasing the wax content more than 15% leads to phase separation. DSC results showed that for all blends both the melting temperature (T_m) and the melting enthalpy (ΔH_m) decrease linearly with an increase in wax content. TGA analysis showed that the thermal stability of all blends decreases linearly with increasing wax content. No clear correlation was observed between the melting point and thermal stability. Horowitz and Metzger method was used to determine the thermal activation energy (E_a). MFI increased exponentially by increasing the wax content. The effect of gamma irradiation on the thermal behavior of the blends was also investigated at different gamma irradiation doses. Significant correlations were found between the thermal parameters (T_m, ΔH_m, T₅%, E_a and MFI) and the amount of wax content and gamma irradiation.