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Potato thermoplastic starch (TPS) containing 1 wt.% of pure halloysite (HNT), glycerol-modified halloysite (G-HNT) or polyester plasticizer-modified halloysite (PP-HNT) was prepared by melt-extrusion. Halloysites were characterized by FTIR, SEM, TGA, and DSC. Interactions between TPS and halloysites were studied by FTIR, SEM, and DMTA. The Vicat softening temperature, tensile, and flexural properties were also determined. FTIR proved the interactions between halloysite and the organic compound as well as between starch, plasticizers and halloysites. Pure HNT had the best thermal stability, but PP-HNT showed better thermal stability than G-HNT. The addition of HNT and G-HNT improved the TPS’s thermal stability, as evidenced by significantly higher T5%. Modified TPS showed higher a Vicat softening point, suggesting better hot water resistance. Halloysite improved TPS stiffness due to higher storage modulus. However, TPS/PP-HNT had the lowest stiffness, and TPS/HNT the highest. Halloysite increased Tα and lowered Tβ due to its simultaneous reinforcing and plasticizing effect. TPS/HNT showed an additional β-relaxation peak, suggesting the formation of a new crystalline phase. The mechanical properties of TPS were also improved in the presence of both pure and modified halloysites.

Silica having amine functional groups (A-SiO2) obtained by the sol-gel process was used to improve compatibility of polyamide 11 and poly(phenylene oxide) (PA11/PPO 80/20) blend via reactive extrusion in a co-rotating twin screw extruder. Amine functional groups of A-SiO2 can react with the carboxyl groups of PA11 to form graft copolymer with PA11 which can efficiently control the phase morphology of the blend. Silica, thanks to the reinforcing effect, significantly increased stiffness of PA11/PPO blend. On the other hand, it greatly improved impact strength and reduced the crystallinity without affecting the crystallization temperature of PA11due to excellent compatibilizing effect. SEM results showed that despite the lower content of PPO, it formed a continuous phase and PA11 - a dispersed. The addition of A-SiO2 changed the morphology from the droplet-matrix to co-continuous with interpenetrating phases. The greatest size-reduction of both phases, reflecting the highest impact toughness, was observed for the content of 3 wt % A-SiO2. With a higher silica loading, phase inversion was observed with the reappearance of the droplet structure, resulting in a slight decrease in impact strength and significant in elongation at break. TGA showed that the composites exhibited better thermal properties as evidenced by the higher initial degradation temperature (Tonset) and the maximum weight loss rate temperature (Tmax).

Poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide 11 (PPO/PA11 80/20) blend filled with neat (SiO2) or modified silica having amine functional groups (A-SiO2) was melt mixing in a twin-screw extruder. The silica was prepared by the sol–gel process. SEM shows that, with increasing A-SiO2 content from 1 to 5 wt.%, the morphology of PPO/PA11blend changed from droplet matrix to co-continuous with phase inversion. The phase inversion was also observed for 5 wt.% of neat silica, but the droplet-matrix structure was retained. The overall rheological and mechanical properties improvement of the A-SiO2-filled composites in comparison with the unfilled blend and neat silica counterpart was drastic, especially in terms of viscosity and stiffness. A-SiO2 improved PPO and PA11 miscibility and reduced the crystallinity of PA11, without affecting the Tc, owing to the compatibilization effect. On the other hand, neat silica slightly increased the crystallinity of PA11 and decreased the crystallization temperature of PA11 and the glass transition temperature of PPO as a result of its plasticization.

HDPE composites, filled with 6 wt.% of unmodified (SiO2) or modified spherical nanosilica, containing immobilized silver (Ag-SiO2) or copper (Cu-SiO2) nanoparticles, differing in filler particle size (30, 60 and 90 nm), were prepared by melt mixing using a twin-screw co-rotating extruder. Maleated HDPE (MHDPE) was used to enhance the interaction between silica and polymer matrix, which facilitated the dispersion of silica. The composites were analyzed using scanning and transmitting electron microscopy (SEM, TEM), dynamic-mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). SEM and TEM results revealed that silica nanoparticles aggregates were in general distributed homogenously. DSC results showed that the incorporation of silica nanoparticles could decrease the melting temperature but increase the crystallization temperature, and could lower the crystallinity degree of the HDPE. Moreover, the homogenous distribution of silica particles in the HDPE significantly affected the thermo-oxidative degradation of the composites. Cu-SiO2 particles of 60 nm dimension in the presence of MHDPE showed the best thermal stability, a maximum increment of 86 °C was obtained compared to the pure HDPE. DMTA results were in good agreement with the findings of the morphological and thermal studies.

Electromagnetic properties of materials are an important topic due to their commercial, military, communication and environmental protection applications [1–14]. Electromagnetic interference (EMI) effects occur due to the emitted EM radiation by electric and/or electronic devices. EMI may affect the devices causing malfunction or fail, which might have very serious consequences, e.g. for medical equipment, aeronautics and cars. Polymer composites with metallic fillers are the subject of increasing interest as potential materials which may effectively shield the electromagnetic field. Polymer composites filled with metal particles are advantageous because they are characterized by low specific weight, high corrosion resistance, plasticity and simple, low cost processing methods. Wide variety of modification of polymer composites (in terms of selection of matrix polymer, type of filler and its structure and content), gives possibility to control their electromagnetic properties depending on particular application. That is why polymer composites with metal fillers are still one of the most important materials to be considered for EMI shielding application. Current review covers theoretical bases and discusses selected experimental results concerning important polymer composites EMI shields developments. Polymer composites EMI shields is a multidisciplinary subject and current review should be useful for the specialist from different areas of research and technology.

The structures and thermal and mechanical properties of poly(phenylene oxide) (PPO) blends with high impact polystyrene (HIPS) were investigated. Two types of PPO were used: commercial one and the other prepared in Industrial Chemistry Research Institute (ICRI) in large laboratory scale process of oxidative polycondensation of 2,6-dimethylphenol, in the presence of complex of copper(II) bromide with morpholine as acatalyst (PPO-IChP). It has been proved that PPO/HIPS blends are miscible in amorphic state, independently on PPO type, because they show the single glass transition temperature, determined by differential scanning calorimetry (DSC) and dynamic­ mechanical thermal analysis (DMTA). Homogeneity of the blends was confirmed by scanning electron microscope (SEM) method. The PPO-IChP/HIPS blend showed significantly higher impact strength and relative elongation at break than PPO-h/HIPS one. The type of PPO used did not influence alot heat distortion heat deflection temperature (HDT) as well as tensile or flexural strength of the blends investigated. PPO-IChP and PPO-IChP/HIPS blend showed aslightly better thermal stability than PPO-h and PPO-h/HIPS blend.

The effect of plasticizer (polydimethylsiloxanol) and neat (SiO2) or modified (having amine functional groups) silica (A-SiO2) on morphology, thermal, mechanical, and rheological properties of PLA/TPS blends compatibilized by maleated PLA (MPLA) was investigated. Toughened PLA/MPLA/TPS (60/10/30) blend containing 3 wt.% of plasticizer and various contents (1, 3, or 5 wt.%) of silica were prepared in a corotating twin-screw extruder. From SEM, it is clear that plasticized PLA/MPLA/TPS blend continuous porous structure is highly related to the silica content and its functionality. The results indicate that polydimethylsiloxanol enhances ductility and the initial thermal stability of the plasticized blend. DSC and DMTA analyses show that nucleation ability and reinforcing effect of A-SiO2on plasticized blend crystallization are much better than those of SiO2. Silica practically had no effect on the thermo-oxidative degradation. However, the composites with A-SiO2had better thermal stability than those with SiO2. Moreover, silica significantly improved the elongation at break.

Modified nanosilica-filled polypropylene composites were manufactured by in situ reactive processing. The key issue lies that amine functional groups of silica nanoparticles reacted with glycidyl methacrylate grafted ethylene/n-octene copolymer (EOC-g-GMA) in order to improve nanofiller dispersion and increase compatibility between silica and PP matrix. Taking the advantages of rubber-type grafted polymer (ethylene/n-octene copolymer) and reactive compatibilization with NH2-SiO2, a synergetic toughening effect was observed for the PP composites. Just very low concentrations of silica nanoparticles (2 wt %) and EOC-g-GMA (4 or 6 wt %) were sufficient to increase significantly notched impact strength and elongation at break of PP. On the contrary, tensile strength of the composites is slightly decreased. Improved dispersion of silica and increased compatibility between silica and PP matrix were observed in the presence of EOC-g-GMA. The crystalline features of PP have not been influenced greatly by addition of both modified silica and compatibilizer. However, the spherulite size of PP dramatically decreased in all composites. The thermal stability of the composites was significantly better compared to PP. Improved stiffness due to increased both storage and loss moduli indicating very good interfacial adhesion was observed.

Summary: The effect of silica containing immobilized nanosilver (SiO2 − Ag) on the structure, mechanical and bactericidal properties of wood-filled high density polyethylene composites compounded in a co-rotating twin-screw extruder and then injection molded was investigated. Maleated high density polyethylene (MHDPE) was used to improve mechanical properties, while spherical nanosilica containing immobilized nanosilver modified bactericidal properties of wood-filled HDPE composites. It was found that the addition of silica in the presence of MHDPE improves adhesion between HDPE and wood fiber. DMTA measurements confirmed these observations, showing toughening effect in the presence of SiO2 − Ag and MHDPE. The gradual enhancement in tensile and flexural strength, elongation and Charpy impact of the wood-filled HDPE composites containing MHDPE and SiO2 − Ag was observed. Nanosilica practically did not affect tensile and flexural moduli of the wood-filled HDPE composites, pointing to a toughing effect. Wood-filled HDPE composites modified with nanosilica containing immobilized nanosilver were found to be active against Escherichia coli, Staphylococcus aureus and Salmonella typhimurium whereas unmodified (without SiO2 − Ag) did not show this efficacy. Thus wood-filled HDPE composites containing SiO2 − Ag are effective bactericidal materials.

Low-density polyethylene/spherical silica (LDPE/SGS) nanocomposites, containing 1, 2, and 6 wt % neat and modified (having amine functional groups) silica nanoparticles, were prepared by melt mixing using a twin-screw corotating extruder. To improve the dispersion degree of the nanoparticles, glicydyl methacrylate grafted ethylene/n-octene copolymer (EOR-g-GMA) containing 0.6 wt % GMA was used as a compatibilizer. It was observed that mechanical properties such as tensile strength, Young's modulus, and impact strength increase and are mainly affected by the loading and size of silica nanoparticles as well as by the EOR-g-GMA. The addition of modified silica and EOR-g-GMA resulted in a further enhancement of mechanical properties due to the improved interfacial adhesion. Storage and loss modulus values of prepared nanocomposites measured by dynamic-mechanical thermal analysis were sensitive to the microstructure of the nanocomposites. Higher storage and loss modulus are evidence that the nanocomposites became stiffer. By adding the modified silica and EOR-g-GMA further increase in storage and loss modulus were observed due to the better dispersion of silica nanoparticles and increased compatibility between silica and the LDPE matrix. Both permitted a much more efficient transfer of stress from the polymer matrix to the silica nanoparticles. The improved barrier properties of all nanocomposites can also be mentioned as a positive effect. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Summary — Polyamide nanocomposites with different octakis(dimethylsiloxy, 3-glycidoxypropyl)octasilsesquioxanes (POSS) contents (0.5, 2, 4 wt. %) were obtained during melt blending. SEM results showed that POSS are uniformly dispersed in polyamide 6 matrix (Fig. 1). FT-IR and DSC analysis indicated that the addition of POSS promotes modifications of the polyamide crystal structure, which consist of the progressive development of crystals and significant increase in the glass transition temperature, crystallization temperature and the crystallization rate of the polyamide 6 (Figs. 2 and 3, Tab. 1). Tensile tests, performed on dried samples, revealed that strength and elongation at break were appreciably modified by the presence of POSS (Fig. 4, Tab. 2). Compared with the neat polyamide 6, the impact strength of PA 6/POSS composites is enhanced (Tab. 2). Dynamic mechanical thermal analysis (DMTA) demonstrated that both the storage modulus (G’) and relaxation temperatures (T, T and T), especially glass transition temperature (T )o f the PA6/POSS composites significantly increased (Fig. 5, Tab. 3).

In the paper a novel preparation method of polyolefin composites of metamaterial properties is presented. The studied composites were obtained by melt mixing of polyolefins and copper flakes of micrometer and/or nanometer-size, as conducting inclusions. The precise control of thickness and structure of the copper layer was achieved by the application of the current pulse and reversed current pulse electrolysis. The structure of the deposited layer on a stainless steel plate and size of copper flakes in polymer composites were studied using a scanning electron microscope (SEM). The electromagnetic properties of prepared metamaterials were measured by split dielectric resonator methods.

The effects of reactive modifiers with anhydride or oxazoline functional groups on the morphology and the mechanical properties of polyolefins waste based blends prepared by melt blending have been studied. The materials were first subjected to morphological analyses by scanning electron microscopy (SEM). The modifiers act as compatibilizers in the structurally heterogeneous blends. Tensile tests showed that the blends had significantly improved elongation and impact strength over their unmodified analogues. Improvements in tensile and impact properties depend on the blend composition and the modifier used.

The effects of reactive extrusion conditions [screw speed (v, 0.67-2.32 s -1 ) and time (t, 60-360 s)] as well as concentration (0.2 or 0.4 wt. %) of compatibilizer [2,2-(1,3-phenylene)-bis(2--oxazoline), PBO] on selected properties of processed blends of polyamide 6 (PA6, 80 wt. %) and poly(ethylene terephthalate) (PET, 20 wt. %) were investigated. The process is carried out in a twin-screw extruder (D = 25 mm, LID = 33) at temperature of plasticizing system equal 245 °C. Dependence of melt flow rate (MFR), viscosity number (LL) and solubility (R) in 85 % formic acid (selective solvent for PA 6) on t (Fig. 1,2 and 4) and v values (Fig. 6, 7, and 9) was investigated and interpreted in details. Generally, t prolongation and v increase cause LL increase and accompanying decrease in MFR. Solubility decreases with prolonged t and increases with v increase. Ambiguous effect of PBO concentration complicates the course of this dependence. FT-IR results and selective solubility estimation proved that block copolymer PA6-block-PBO-block-PET [equation (1)] formed during the process investigated.

Polyamide 6 (PA) was blended with poly(butylene terephthalate) (PBT) in the 80/20 wt/wt ratio, either with or without addition of small amounts (0.2 or 0.4 phr) of 2,2′-(1,3-phenylene)-bis(2-oxazoline) (PBO). The reactions of PBO with blend components were studied by Fourier transform infra red spectroscopy (FT-IR), solubility behaviour of the products in formic acid and rheological measurements. PA/PBT blends were prepared in a co-rotating twin-screw extruder and characterized by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The static tensile properties, and impact strength of the blends were tested. The results indicate that the reactions of PBO with free carboxyl end groups of PA and PBT occur, at least in part, to form PA-co-PBO-co-PBT copolymers acting as effective compatibilisers for these blends. However, PBO reacts more rapidly with PBT than with PA, probably due to the lower molar mass and/or the more uniform distribution of the reactive oxazoline groups of PBT.

The post-production PET-containing fabrics wastes were recycled in order to produce new higher added value polymeric materials using reactive extrusion. These wastes were melt blended with polyamide 6 (PA6) and reactive modifier (M) elaborated in Industrial Chemistry Research Institute in Warsaw. The modifier acts as compatibilizer in the structurally heterogenous initial PA6/PET blends. PA6-block-M-block-PET copolymers formed during the reactive extrusion and located at the interface resulted in good interfacial adhesion, improved tensile properties and high impact strength of these blends.

The effects of an addition of polyethylene functionalized with ricinol-2-oxazoline methyl maleate (PE-g-MRO), acting as compatibilizer, on the morphology, phase transitions and selected mechanical properties of the blendsconsisted of thermoplastic polyester elastomer/polyamide 6 (TPE-E/ PA6) prepared by reactive extrusion were investigated. Thermodynamic parameters (glass transition temperature, temperature and enthalpy of crystallization and melting transitions of the blends versus their compositions) were determined using differential scanning calorimetry (DSC, Table 2, Figs. 1-3). Morphology of TPE-E/PE-g-MRO/PA6 blends has been characterized by scanning electron microscopy (SEM). Furthermore the static tensile and flexural properties as well as Charpy impact strength and heat distortion temperature (Table 4) were tested. It has been found that the blends investigated showed compatible heterogenic structure (Figs. 4, 5) formed during reactive extrusion as a result of the reactions of functional groups of TPE-E, PA 6 or PE-g-MRO. The structure stabilizes on the microphase level what let obtain high impact strength and excellent mechanical properties of the blends (Table 4, Fig. 6). SEM results are in agreement with DSC results as well as with the results of formic acid extraction (Table 3) and suggest the formation of new TPE-E-block-PA6 copolymers, increasing the interfacial interactions. The results confirm the effective action of PE-g-MRO as a compatibilizer for TPE-E/ PA6 blends causing the improvement of majority of functional properties, mainly impact strength, of these blends.

Effect of PE-LD grafting with ricinol-2-oxazoline methylmaleate (MRO) on phase structure as well as thermal and mechanical properties of polyamide 6 and low-density polyethylene blends (PA 6/PE-LD-g-MRO), differing in composition, obtained in reactive extrusion process, has been studied. This effect was studied using the following methods: infrared spectroscopy (FT-IR, Fig. 1 and 2), differential scanning calorimetry (DSC, Fig. 3 and 4, Table 1 and 2), scanning electron microscopy (SEM, Fig. 5) and dynamic mechanical/thermal analysis (DMTA, Figs. 6-10). The blends show heterogenic structure which, as a result of chemical reactions going during the extrusion, stabilizes at microphase level [probably of functional groups of PA 6 with oxazoline groups grafted onto PE according to equation (2)]. It advantageously influences mechanical properties (Tables 3-5, Fig. 11). Results of investigations show the compatibilizing effect of MRO.

Structural phases and blends properties of poly(butylene terephthalate)/polyamide 6 blends were studied in a chemical modification involving reactive extrusion with a ricinol-2-oxazoline methylmaleate (ROM) grafted polyethylene. The interfacial reaction between blend components were studied by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The static tensile and flexural properties and impact resistance response of the blends were tested. According to DSC data, the reactive processing results in formation of heterogenous blends. Phase structure and mechanical behavior studies showed that interfacial reactions between PE-g-ROM, poly(butylene terephthalate) and polyamide 6 containing co-reactive groups were effective in the compatibilization of blends investigated. Phase morphology of the blends was of interpenetrating polymer network (IPN) type according to SEM results which was in accordance with learnings from DTA spectra. FT-IR, DSC and DTA investigations suggest evidence for the chemical reaction. The graft polymer formed during the reactive extrusion results in an alloy with good interfacial adhesion and high impact resistance.

A series of mica filled PET scrap/PE-g-ROM blends was studied in a chemical modification involving reactive extrusion with a ricinoloxazoline maleinate. Studies were conducted concerning mechanical properties (flexural and impact strength), thermal properties (DSC and Vicat softening temperature) and flame retardancy. The phase morphology of the blends was of interpenetrating network (IPN) type according to SEM results. Mica filled blends offer good mechanical properties, reduced flammability and increased Vicat point. The composition with 30% of mica gives the best properties and efficiency in reducing the rate of burning.

Polyethylene, polyamide 6 and poly(ethylene terephthalate) multilayer films waste were recycled by reactive extrusion in order to produce thermoplastic polymers. These wastes were extruded together with PA 6 and PET functionalized with oxazoline groups (R-PA 6, R-PET), ethylene/acrylic acid copolymer (EAA) or block copolymer styrene-ethylene/butylene-styrene-grafted-succinic acid (SEBS-g-SA). Used additives act as compatibilizers in the structurally heterogeneous initial wastes. Compatibilizers used, as well as wood fiber granulates (filler), improve the mechanical properties of compositions investigated.

Silica containing immobilized nanosilver (Ag-SiO2) or nanocopper (Cu-SiO2) was used as a filler for high-density polyethylene (HDPE). The HDPE/Ag-SiO2and HDPE/Cu-SiO2composites were prepared by melt blending and injection molding. The microstructure of the composites was examined using transmission electron microscopy (TEM). The crystallization behavior and thermal properties were studied using differential scanning calorimetry (DSC) and thermogravimetry (TGA). The mechanical properties were characterized by tensile, flexural, and impact tests as well as dynamic mechanical thermal analysis (DMTA). The ability of silica to give antimicrobial activity to HDPE was also investigated and discussed. The TEM images indicate that Ag-SiO2show lower degree of agglomeration than Cu-SiO2nanoparticles. The crystallization temperature increased, whereas crystallinity decreased in the composites. The thermal stability of the composites was significantly better compared to HDPE. Improved stiffness indicating very good interfacial adhesion was observed. Excellent activity against different kinds of bacteria was found.

A series of PET/R-PP/PC blends was studied in a chemical modification involving reactive extrusion with a ricinyl-2-oxazoline maleinate. The interfacial reaction between blend components were studied by the differential scanning calorimetry (DSC) and the scanning electron microscopy (SEM). The static tensile and flexural properties, and impact resistance response of the blends were tested. The phase morphology of the blends was of interpenetrating network (IPN) type according to SEM results. The blends offer excellent mechanical properties and improved impact strength as an effect of chemical reactions on reactive extrusion, even if PET waste and low PC contents (below 20%) have been used.

Structural phases and blends properties of glass fiber filled reactive PET/R-PE blends (85/15 and 75/25 wt/wt) were studied in a chemical modification involving reactive extrusion with a ricinyl-2-oxazoline maleate. The present method offers compatible heterogenous blends with the structure stabilized at microphase level and with advantageous macroscopic properties, viz., impact and tensile resistance, processability. The most important effects of glass fiber reinforcement are increases in strength (tensile and flexural) and stiffness (flexural modulus).

Mechanical behavior of graphite-filled recycled polycarbonate/maleic anhydride grafted polyethylene [PC/PE-g-MAH (80/20)] composites prepared by melt blending was investigated. The materials were first subjected to morphological analyses using wide-angle X-ray scattering (WAXS) and scanning electron microscopy (SEM). The modifier acts as a reactive compatibilizer in the structurally heterogeneous PC/PE blends. Tensile tests showed that stiffness, strength, and ductility were markedly modified by the presence of graphite in the composites. Furthermore, an enhancement of thermal stability was observed, without any significant deterioration of the mechanical properties. The relationships among these effects and microstructural characteristics of the products obtained were also analyzed.