Crystallization Behaviour of TiO2 Nanoparticle Reinforced Polypropylene

Composites of isotactic polypropylene (iPP) with different TiO2 nanoparticle loads (0.5 vol.%, 2 vol.% and 4 vol.%) were compounded by optimized twin screw extrusion. The crystallization behaviour of these semicrystalline nanocomposites was examined by differential scanning calorimetry (DSC), scanning electron microscope (SEM) and polarized optical light microscope (POM) combined with a hot stage module to pursue in-situ the structure development. Wet chemical etching was applied to highlight morphological details like spherulites and lamellar structures for SEM observations. An obvious influence of TiO2-nanoparticles on the crystallization could be verified.

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Plasticized Biodegradable Poly(lactic acid) Based Composites Containing Cellulose in Micro- and Nanosize

Journal of Engineering ◽

10.1155/2013/329379 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 29

Author(s):

Katalin Halász ◽

Levente Csóka

Keyword(s):

Lactic Acid ◽

Microcrystalline Cellulose ◽

Composite Films ◽

Poly Lactic Acid ◽

Twin Screw Extrusion ◽

Scanning Calorimetry ◽

Screw Extrusion ◽

Twin Screw ◽

Biodegradable Poly ◽

Poly Ethylene

The aim of this work was to study the characteristics of thermal processed poly(lactic acid) composites. Poly(ethylene glycol) (PEG400), microcrystalline cellulose (MCC), and ultrasound-treated microcrystalline cellulose (USMCC) were used in 1, 3, and 5 weight percents to modify the attributes of PLA matrix. The composite films were produced by twin screw extrusion followed by film extrusion. The manufactured PLA-based films were characterized by tensile testing, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD), and degradation test.

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Evaluation of the Degradation Properties of Carbonate Substituted Hydroxyapatite-Poly(ε-caprolactone) Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.493-494.120 ◽

2011 ◽

Vol 493-494 ◽

pp. 120-125 ◽

Cited By ~ 2

Author(s):

Duygu Ege ◽

Koonyang Lee ◽

Alexandre Bismarck ◽

Serena Best ◽

Ruth Cameron

Keyword(s):

Degradation Rate ◽

Polymer Surface ◽

Twin Screw Extrusion ◽

Wet Chemical Synthesis ◽

Screw Extrusion ◽

Twin Screw ◽

Wet Chemical ◽

Degradation Properties ◽

Degradation Time

The aim of this work is to produce and characterise carbonate substituted hydroxyapatite (CHA) reinforced polycaprolactone (PCL) nanocomposites with a controlled degradation rate in order to match the rate of bone in-growth. The ideal degradation time for this purpose is estimated to be around 5-6 months however, in vivo, PCL degrades over a period of 2 to 3 years. It has been reported that NaOH surface treatment can accelerate the degradation of PCL [1-3]. In order to further modify the degradation rate of PCL, the effects of the incorporation of different volume fractions of CHA in samples surface treated with NaOH was investigated. CHA was produced by wet chemical synthesis. Samples comprising 8, 19, 25 wt% uncalcined CHA-PCL composites were produced by twin screw extrusion which were then injection moulded into cylinders. In order to accelerate the degradation rate of PCL, it was surface treated with 5 M NaOH for 3 days prior to PBS studies. The degradation profile was examined by % weight loss and % water uptake measurements. NaOH treatment was observed to erode the polymer surface and the polymer-filler interface. On subsequently degrading the pre-treated samples in PBS, it was observed that with increasing fraction of CHA, the degradation rate in PBS of the sample increased. Up to 8 wt % CHA filler there appeared to be little change in the degradation properties of the NaOH treated samples with the onset occurring after 60 days. However there was a marked acceleration of degradation for samples containing 19 wt% when degradation appeared to occur immediately. In conclusion, the addition of CHA significantly affects the behaviour of PCL.

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Influence of the Conditions of Corotating Twin-Screw Extrusion for Talc-Filled Polypropylene on Selected Properties of the Extrudate

Polymers ◽

10.3390/polym11091460 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1460 ◽

Cited By ~ 1

Author(s):

Sasimowski ◽

Majewski ◽

Grochowicz

Keyword(s):

Maximum Tensile Stress ◽

Extrusion Process ◽

Twin Screw Extrusion ◽

Screw Extruder ◽

Scanning Calorimetry ◽

Melt Flow Rate ◽

Test Segment ◽

Screw Extrusion ◽

Twin Screw

The aim of the study was to determine the effect of the application of processing screws with a modified test segment in a corotating twin-screw extruder on selected properties of talc-filled polypropylene extrudate. The test segment was built of trilobe kneading elements and its design modifications refered to changing the distance between the kneading elements and the angle of positions of kneading elements that are relative to each other. The performed tests included the production of extrudate with various degrees of talc-filling using five design solutions of the test segment and then measurements of selected properties, such as tensile strength, elongation at maximum tensile stress, and melt flow rate. Structural studies using scanning electron microscope (SEM) and differential scanning calorimetry (DSC) were also carried out. The study includes not only the description of experimental results but also the determination of empirical models describing the dependence of the properties of the obtained extrudate on the conditions of the extrusion process and the design features of the test segment.

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PLA/PA Bio-Blends: Induced Morphology by Extrusion

Polymers ◽

10.3390/polym12010010 ◽

2019 ◽

Vol 12 (1) ◽

pp. 10 ◽

Cited By ~ 1

Author(s):

Violeta García-Masabet ◽

Orlando Santana Pérez ◽

Jonathan Cailloux ◽

Tobias Abt ◽

Miguel Sánchez-Soto ◽

...

Keyword(s):

Mechanical Performance ◽

Reactive Extrusion ◽

Processing Parameters ◽

Poly Lactic Acid ◽

Twin Screw Extrusion ◽

Extrusion Die ◽

Screw Extrusion ◽

Twin Screw ◽

Speed Rotation

The effect of processing conditions on the final morphology of Poly(Lactic Acid) (PLA) with bio-based Polyamide 10.10 (PA) 70/30 blends is analyzed in this paper. Two types of PLA were used: Commercial (neat PLA) and a rheologically modified PLA (PLAREx), with higher melt elasticity produced by reactive extrusion. To evaluate the ability of in situ micro-fibrillation (μf) of PA phase during blend compounding by twin-screw extrusion, two processing parameters were varied: (i) Screw speed rotation (rpm); and (ii) take-up velocity, to induce a hot stretching with different Draw Ratios (DR). The potential ability of PA-μf in both bio-blends was evaluated by the viscosity (p) and elasticity (k’) ratios determined from the rheological tests of pristine polymers. When PLAREx was used, the requirements for PA-μf was fulfilled in the shear rate range observed at the extrusion die. Scanning electron microscopy (SEM) observations revealed that, unlike neat PLA, PLAREx promoted PA-μf without hot stretching and the aspect ratio increased as DR increased. For neat PLA-based blends, PA-μf was promoted during the hot stretching stage. DMTA analysis revealed that the use of PLAREx PLAREx resulted in a better mechanical performance in the rubbery region (T > Tg PLA-phase) due to the PA-μf morphology obtained.

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The Effect of Poly(Butylene Adipate-co-Terephthalate) on Crystallization Behavior and Morphology of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.798.343 ◽

2019 ◽

Vol 798 ◽

pp. 343-350

Author(s):

Sitthi Duangphet ◽

Damian Szegda ◽

Karnik Tarverdi ◽

Jim Song

Keyword(s):

Crystal Structure ◽

Crystallization Behavior ◽

X Ray Diffraction ◽

Twin Screw Extrusion ◽

Scanning Calorimetry ◽

Sem Images ◽

X Ray ◽

Screw Extrusion ◽

Twin Screw ◽

Matrix Morphology

The effects of poly(butylene adipate-co-terephthalate) (PBAT) on crystallization behavior and morphology of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were studied to provide the useful information to control and improve PHBV processing. PHBV were blended with 15, 30 and 50 wt% PBAT by twin screw extrusion and these were subsequently compared to unblended PHBV. The rate of crystal development determined from differential scanning calorimetry (DSC) at 120 °C showed that the incorporation of PBAT retarded the crystal growth rate. Moreover, the crystal structure of polymer blends was examined by X-ray diffraction (XRD) and the results revealed that PBAT did not affect the crystal structure of PHBV. The responses of the melt-crystallized PHBV to different quantities of PBAT were recorded by polarized optical microscopy (POM). The results demonstrated that the size of spherulite dramatically increased when 15 wt% PBAT was added and the shape of spherulite was imperfect when PBAT reached 30 wt%. The morphologies of PHBV and its blends on the freeze-fractured specimens were exposed using scanning electron microscopy (SEM). The SEM images revealed the phase separation of PHBV/ PBAT blends in any composition. The morphology of 15 and 30 wt% PBAT presented droplet in matrix morphology and changed to co-continuous morphology at 50 wt% PBAT.

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Extruded PLA Nanocomposites Modified by Graphene Oxide and Ionic Liquid

Polymers ◽

10.3390/polym13040655 ◽

2021 ◽

Vol 13 (4) ◽

pp. 655

Author(s):

Cristian Sánchez-Rodríguez ◽

María-Dolores Avilés ◽

Ramón Pamies ◽

Francisco-José Carrión-Vilches ◽

José Sanes ◽

...

Keyword(s):

Ionic Liquid ◽

Graphene Oxide ◽

Viscoelastic Behavior ◽

Mechanical Analysis ◽

Twin Screw Extrusion ◽

Scanning Calorimetry ◽

Screw Extrusion ◽

Ir And Raman Spectroscopies ◽

Twin Screw ◽

Ft Ir

Polylactic acid (PLA)-based nanocomposites were prepared by twin-screw extrusion. Graphene oxide (GO) and an ionic liquid (IL) were used as additives separately and simultaneously. The characterization of the samples was carried out by means of Fourier transform infrared (FT-IR) and Raman spectroscopies, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The viscoelastic behavior was determined using dynamic mechanical analysis (DMA) and rheological measurements. IL acted as internal lubricant increasing the mobility of PLA chains in the solid and rubbery states; however, the effect was less dominant when the composites were melted. When GO and IL were included, the viscosity of the nanocomposites at high temperatures presented a quasi-Newtonian behavior and, therefore, the processability of PLA was highly improved.

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Bio-Based PBT–DLA Copolyester as an Alternative Compatibilizer of PP/PBT Blends

Polymers ◽

10.3390/polym11091421 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1421 ◽

Cited By ~ 2

Author(s):

Ignaczak ◽

Sobolewski ◽

El Fray

Keyword(s):

Gel Permeation Chromatography ◽

Mechanical Analysis ◽

Resonance Spectroscopy ◽

Twin Screw Extrusion ◽

Scanning Calorimetry ◽

Butylene Terephthalate ◽

Screw Extrusion ◽

Twin Screw ◽

Static Tensile ◽

Copolymer Poly

The aim of this work was to assess whether synthesized random copolyester, poly(butylene terephthalate-r-butylene dilinoleate) (PBT–DLA), containing bio-based components, can effectively compatibilize polypropylene/poly(butylene terephthalate) (PP/PBT) blends. For comparison, a commercial petrochemical triblock copolymer, poly(styrene-b-ethylene/butylene-b-styrene) (SEBS) was used. The chemical structure and block distribution of PBT–DLA was determined using nuclear magnetic resonance spectroscopy and gel permeation chromatography. PP/PBT blends with different mass ratios were prepared via twin-screw extrusion with 5 wt% of each compatibilizer. Thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis were used to assess changes in phase structure of PP/PBT blends. Static tensile testing demonstrated marked improvement in elongation at break, to ~18% and ~21% for PBT–DLA and SEBS, respectively. Importantly, the morphology of PP/PBT blends compatibilized with PBT–DLA copolymer showed that it is able to act as interphase modifier, being preferentially located at the interface. Therefore, we conclude that by using polycondensation and monomers from renewable resources, it is possible to obtain copolymers that efficiently modify blend miscibility, offering an alternative to widely used, rubber-like petrochemical styrene compatibilizers.

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