Performance of polylactide against UV irradiation: Synergism of an organic UV absorber with micron and nano-sized TiO2

2020 ◽  
Vol 54 (18) ◽  
pp. 2489-2504 ◽  
Author(s):  
Ulas Can ◽  
Cevdet Kaynak
Keyword(s):  
Weight Loss ◽  
Thermal Properties ◽  
Uv Irradiation ◽  
Chemical Structure ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Melt Mixing ◽  
Uv Absorber ◽  
Fluorescent Lamps ◽  
Twin Screw

The main purpose of this study was to investigate mechanical and thermal performance of polylactide specimens against UV irradiation; first when only adding benzotriazole benzotriazole-based organic UV absorber (UVA), micro (200 nm) and nano (50 nm) sized titania (TiO2) particles alone, and then to reveal possible synergism when they are added together. Compounds were prepared by twin-screw extruder melt mixing, while the 2 mm thick specimens were shaped by compression molding. Specimens were exposed to UV irradiation under fluorescent lamps (UVB-313) with 0.50 W/m2 for the periods of 12 and 24 days. Changes in the performance of UV irradiated specimens were evaluated in terms of % weight loss, changes in color and chemical structure, including the decreases in the mechanical and thermal properties. Various tests and analysis revealed that synergistic benefits of using micro and nano TiO2 particles together with benzotriazole-type UVA were not only due to the effective stiffening, strengthening and toughening actions of titania particles, but also due to their very significant “UV screening” actions absorbing the photons of the UV irradiation, thus decreasing the degree of the detrimental photodegradation reactions leading to chain scissions in their PLA matrix.

Mechanical and thermal characterization of grafted PP-NCC nanocomposites

2019 ◽  
pp. 089270571987822
Author(s):  
Saud Aldajah ◽  
Mohammad Y Al-Haik ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik
Keyword(s):  
Thermal Properties ◽  
Interfacial Adhesion ◽  
Thermal Characterization ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Three Point Bending ◽  
Twin Screw ◽  
Thermal Stability Of

This study reveals the enhancement of mechanical and thermal properties of maleic anhydride-grafted polypropylene (PP- g-MA) with the addition of nanocrystalline cellulose (NCC). A nanocomposite was manufactured by blending various percentages of PP, MA, and NCC nanoparticles by means of a twin-screw extruder. The influence of varying the percentages of NCC on the mechanical and thermal behavior of the nanocomposite was studied by performing three-point bending, nanoindentation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy tests. The novelty of this study stems on the NCC nanoparticles and their ability to enhance the mechanical and thermal properties of PP. Three-point bending and nanoindentation tests revealed improvement in the mechanical properties in terms of strength, modulus, and hardness of the PP- g-MA nanocomposites as the addition of NCC increased. SEM showed homogeneity between the mixtures which proved the presence of interfacial adhesion between the PP- g-MA incorporated with NCC nanoparticles that was confirmed by the FTIR results. DSC and TGA measurements showed that the thermal stability of the nanocomposites was not compromised due to the addition of the coupling agent and reinforced nanoparticles.

Behaviour of PLA/POSS nanocomposites: Effects of filler content, functional group and copolymer compatibilization

2021 ◽  
pp. 096739112110080
Author(s):  
Yelda Meyva Zeybek ◽  
Cevdet Kaynak
Keyword(s):  
Functional Group ◽  
Filler Content ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Melt Mixing ◽  
Grafted Copolymer ◽  
Before And After ◽  
Twin Screw ◽  
Oligomeric Silsesquioxane ◽  
Matrix Nanocomposites

The main purpose of this study was to investigate influences of three parameters on the mechanical and thermal properties of the polylactide (PLA) matrix nanocomposites filled with polyhedral oligomeric silsesquioxane (POSS) particles. For the first parameter of “Filler Content”, nanocomposites with 1, 3, 5, 7 wt% basic POSS structure were compared. For the second parameter of “Functional Group,” basic POSS structure having only nonpolar isobutyl groups were compared with three other functionalized POSS structures; i.e. aminopropylisobutyl-POSS (ap-POSS), propanediolisobutyl-POSS (pd-POSS) and octasilane-POSS (os-POSS). Finally, for the third parameter of “Copolymer Compatibilization,” all specimens were compared before and after their maleic anhydride (MA) grafted copolymer compatibilization. Specimens were produced with twin-screw extruder melt mixing and shaped under compression molding. Various tests and analyses indicated that the optimum filler content for the improved mechanical properties was 1 wt%; while the optimum structure for strength and modulus was pd-POSS structure, in terms of fracture toughness it was basic POSS structure. Additional use of MA compatibilization was especially effective for the basic POSS and os-POSS particles.

Structure and Properties of Recycled Aromatic Thermoplastic Polyester Nanocomposites

2012 ◽  
Vol 527 ◽  
pp. 44-49
Author(s):  
Remo Merijs Meri ◽  
Janis Zicans ◽  
Tatjana Ivanova ◽  
Rita Berzina ◽  
Guntis Japins ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Mechanical And Thermal Properties ◽  
Structure And Properties ◽  
Screw Extruder ◽  
Melt Compounding ◽  
Weight Content ◽  
Recycled Polyethylene ◽  
Twin Screw ◽  
Nanofiller Content ◽  
Montmorillonite Nanoclay

Structure as well as mechanical and thermal properties of the nanocomposites based on recycled polyethylene terephthalate (RPET) are investigated. 1, 2 and 5 wt. % of unmodified montmorillonite nanoclay (MMT) were introduced in the RPET matrix by melt compounding in a twin screw extruder. Results of the investigations testify that optimum content of MMT for modification of RPET is between 1 and 2 wt. %. Up to this nanofiller weight content, the most rapid increase of stiffness, strength and impact toughness is observed. Besides it, at this nanofiller weight content the investigated composite have somewhat improved thermal resistance. It is demonstrated that the improvement of these properties is due to better distribution of MMT in the polymer matrix. At higher nanofiller content, the undesirable effects of the nanofiller agglomeration becomes more important.

Morphological, mechanical, and thermal properties of PP/SEBS/talc composites

2019 ◽  
pp. 089270571987667 ◽  
Author(s):  
Carlos Ivan Ribeiro de Oliveira ◽  
Marisa Cristina Guimarães Rocha ◽  
Joaquim Teixeira de Assis ◽  
Ana Lúcia Nazareth da Silva
Keyword(s):  
Thermal Properties ◽  
Impact Resistance ◽  
Mechanical And Thermal Properties ◽  
Processing Conditions ◽  
Screw Extruder ◽  
Crystallinity Degree ◽  
Twin Screw ◽  
The Impact ◽  
Scanning Electron ◽  
Nucleating Effect

The aim of this study is to evaluate the effect of some experimental variables such as the content of styrene–ethylene–butylene–styrene (SEBS) and talc, processing conditions and mixing protocol on the properties of polypropylene (PP). To achieve this objective, PP/SEBS blends and PP/SEBS/talc composites were processed in a corotating twin-screw extruder. A masterbatch of PP/talc was prepared before the extrusion of PP/SEBS/talc composites. The morphology of blends and composites was evaluated by scanning electron microscopy, which revealed the dispersion of small rubber droplets in the PP matrix. Moreover, the micrographs also showed that SEBS and talc particles were uniformly dispersed and distributed in the polymer matrix. Results of thermal properties showed that talc had a nucleating effect, which promoted the increase of both PP crystallization temperature and crystallinity degree. The incorporation of talc in PP/SEBS blends led to an expressive increase in the impact resistance by 70% as compared with the reference blend: PP/SEBS 80/20% (w/w). This result reveals that although the PP/SEBS/talc composites showed a separated morphology, the good dispersion and distribution of this mineral filler in the polymers contributed to avoid crack propagation and increase the impact properties. The tensile properties in the elastic region were not significantly affected.

scholarly journals Mechanical and thermal properties of bacterial-cellulose-fibre-reinforced Mater-Bi® bionanocomposite

2013 ◽  
Vol 4 ◽  
pp. 325-329 ◽  
Author(s):  
Hamonangan Nainggolan ◽  
Saharman Gea ◽  
Emiliano Bilotti ◽  
Ton Peijs ◽  
Sabar D Hutagalung
Keyword(s):  
Thermal Properties ◽  
Bacterial Cellulose ◽  
Volume Fraction ◽  
Cellulose Fibre ◽  
Tensile Tests ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Elongation At Break ◽  
Freeze Dried ◽  
Twin Screw

The effects of the addition of fibres of bacterial cellulose (FBC) to commercial starch of Mater-Bi® have been investigated. FBC produced by cultivating Acetobacter xylinum for 21 days in glucose-based medium were purified by sodium hydroxide 2.5 wt % and sodium hypochlorite 2.5 wt % overnight, consecutively. To obtain water-free BC nanofibres, the pellicles were freeze dried at a pressure of 130 mbar at a cooling rate of 10 °C min−1. Both Mater-Bi and FBC were blended by using a mini twin-screw extruder at 160 °C for 10 min at a rotor speed of 50 rpm. Tensile tests were performed according to ASTM D638 to measure the Young’s modulus, tensile strength and elongation at break. A field emission scanning electron microscope was used to observe the morphology at an accelerating voltage of 10 kV. The crystallinity (T c) and melting temperature (T m) were measured by DSC. Results showed a significant improvement in mechanical and thermal properties in accordance with the addition of FBC into Mater-Bi. FBC is easily incorporated in Mater-Bi matrix and produces homogeneous Mater-Bi/FBC composite. The crystallinity of the Mater-Bi/FBC composites decrease in relation to the increase in the volume fraction of FBC.

scholarly journals Structural and Thermal Properties of Starch Plasticized with Glycerol/Urea Mixture

2021 ◽  
Author(s):  
Magdalena Paluch ◽  
Justyna Ostrowska ◽  
Piotr Tyński ◽  
Waldemar Sadurski ◽  
Marcin Konkol
Keyword(s):  
Thermal Properties ◽  
Chemical Structure ◽  
Gel Permeation Chromatography ◽  
Xrd Analysis ◽  
Thermoplastic Starch ◽  
X Ray Diffraction ◽  
Screw Extruder ◽  
X Ray ◽  
Twin Screw ◽  
Starch Retrogradation

AbstractThe paper presents the results of research on the influence of used plasticizing system on the structural and thermal properties of thermoplastic starch (TPS). The thermoplastic starch granulate was obtained by extrusion of native starch in the presence of a plasticizing system using a twin-screw extruder. Glycerol and urea were used as plasticizers in various proportions. In order to evaluate the effectiveness of the starch plasticization process, changes in its chemical structure were analyzed by infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and X-ray diffraction (XRD). TPS thermal stability was determined by thermogravimetric analysis (TGA). An improvement in the efficiency of the plasticization process has been found for a urea-containing plasticizing system compared to the composition of starch plasticized only with glycerol. In addition, the XRD analysis confirms the beneficial effect of urea on the inhibition of starch retrogradation process.

Preparation, Mechanical and Thermal Properties of PLA/PBAT/EGMA Blends

2018 ◽  
Vol 783 ◽  
pp. 18-22
Author(s):  
He Zhi He ◽  
Bi Da Liu ◽  
Bin Xue ◽  
Zhi Wen Zhu ◽  
Feng Xue ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Glycidyl Methacrylate ◽  
Chemical Structure ◽  
Testing Machine ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Interface Bonding ◽  
Screw Extruder ◽  
Elongation At Break ◽  
Ethylene Methyl Acrylate

Poly(lactic acid) (PLA)/Poly(butylene-adipate-co-terephthalate) (PBAT) blends were prepared through corotating tri-screw extruder. Ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EGMA) was used as a reacting compatibilizer to increase the interface bonding force. The effect of EMGA on the mechanical properties, thermal properties and chemical structure of PLA/PBAT blends were researched respectively through multi-use mechanical testing machine, differential scanning calorimeter and Fourier transform infrared spectroscopy. The results indicate that the compatibility between PLA and PBAT could be enhanced by incorporating EGMA, and all of the blends with EGMA showed increase in impact strength and elongation at break. PLA/PBAT blends showed optimum elongation at break with 6% of EGMA. DSC study also indicated the greatest crystallinity when adding 6% of EGMA. Excessive addition of EGMA instead reduced the crystallinity and elongation at break.

Effect of Compatibilizer on Impact Strength and Morphology of Polystyrene/Zinc Oxide Nanocomposites

2012 ◽  
Vol 545 ◽  
pp. 330-334
Author(s):  
Sirirat Wacharawichanant ◽  
Pranee Saetun ◽  
Thunwawon Lekkong ◽  
Thongyai Supakanok
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Impact Strength ◽  
Impact Test ◽  
Screw Extruder ◽  
Melt Mixing ◽  
Zno Particles ◽  
Twin Screw ◽  
The Impact ◽  
Scanning Electron

This article investigated the effects of particle size of zinc oxide (ZnO) and polystyrene-co-maleic anhydride (SMA) compatibilizer on impact strength and morphology of polystyrene (PS)/ZnO71 (71 nm) and PS/ZnO250 (250 nm) nanocomposites. PS/ZnO nanocomposites with varying concentration of ZnO and SMA were prepared by a melt mixing technique in a twin screw extruder. It was found that the impact strength of PS nanocomposites increased up to a ZnO content of 1.0 wt%. Moreover, PS/ZnO250 nanocomposites had higher impact strength than PS/ZnO71 nanocomposites. The addition of SMA increased the impact strength of PS/ZnO nanocomposites with increasing SMA content. The result showed that SMA could improve impact strength of nanocomposites. The dispersion of ZnO particles on PS/ZnO nanocomposites was studied by scanning electron microscope (SEM). It was observed that the dispersion of ZnO particles of PS/ZnO nanocomposites without SMA was non-uniform and the agglomeration of ZnO particles in the polymer matrix increased with increasing ZnO content. The dispersion of ZnO particles of PS/ZnO nanocomposites after adding SMA was relatively good and only few aggregations exist. These observations support the results of the impact test where the PS/ZnO nanocomposites with SMA displayed higher impact strength than the PS/ZnO nanocomposites without SMA. The study showed that SMA was used as a compatibilizer to improve the dispersability and compatibility of ZnO particles in PS matrix.

Anhydride/Epoxy Functionalized Blends: Mechanical, Rheological and Thermal Properties

2001 ◽  
Vol 702 ◽  
Author(s):  
Goknur Bayram ◽  
Ulku Yilmazer
Keyword(s):  
Thermal Properties ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Chain Extension ◽  
Screw Extruder ◽  
Batch Mixing ◽  
Twin Screw ◽  
Styrene Maleic Anhydride ◽  
Batch Mixer ◽  
Fine Morphology

ABSTRACTBlends of styrene-maleic anhydride (SMAH) and polyethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) were produced in a batch mixer and in a corotating twin screw extruder. E-MA-GMA concentration was varied from 0 % to 50 %. Batch mixing indicated that the blend system was reactive. Extruded blends were characterized in terms of rheological, thermal and mechanical properties, and their morphology was observed. Rheological properties such as the storage modulus, loss modulus and complex viscosity exhibited maxima at 25 % EMA-GMA content. The blends had fine morphology as observed by scanning electron microscopy. Thermal properties were not significantly affected by the change in epoxy concentration. As E-MA-GMA concentration increased, tensile strength and modulus of elasticity decreased, but percent strain at break increased. These observations could be explained in terms of the chain extension / branching reactions that occurred in mixing the blends.

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