The Effect of Surface Treatment with Isocyanate and Aromatic Carbodiimide of Thermally Expanded Vermiculite Used as a Functional Filler for Polylactide-Based Composites

In this work, thermally expanded vermiculite (TE-VMT) was surface modified and used as a filler for composites with a polylactide (PLA) matrix. Modification of vermiculite was realized by simultaneous ball milling with the presence of two PLA chain extenders, aromatic carbodiimide (KI), and 4,4’-methylenebis(phenyl isocyanate) (MDI). In addition to analyzing the particle size of the filler subjected to processing, the efficiency of mechanochemical modification was evaluated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The composites of PLA with three vermiculite types were prepared by melt mixing and subjected to mechanical, thermomechanical, thermal, and structural evaluation. The structure of composites containing a constant amount of the filler (20 wt%) was assessed using FTIR spectroscopy and SEM analysis supplemented by evaluating the final injection-molded samples’ physicochemical properties. Mechanical behavior of the composites was assessed by static tensile test and impact strength hardness measurements. Heat deflection temperature (HDT) test and dynamic thermomechanical analysis (DMTA) were applied to evaluate the influence of the filler addition and its functionalization on thermomechanical properties of PLA-based composites. Thermal properties were assessed by differential scanning calorimetry (DSC), pyrolysis combustion flow calorimetry (PCFC), and thermogravimetric analysis (TGA). The use of filler-reactive chain extenders (CE) made it possible to change the vermiculite structure and obtain an improvement in interfacial adhesion and more favorable filler dispersions in the matrix. This translated into an improvement in impact strength and an increase in thermo-mechanical stability and heat release capacity of composites containing modified vermiculites.

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Study on the Crystallization and Morphology of HDPE-g-GMA Modified PA66/UHMWPE Blends

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.123-125.239 ◽

2010 ◽

Vol 123-125 ◽

pp. 239-242

Author(s):

Zi Nian Zhao ◽

Wen Hua Zhang ◽

Gang Qiang Lei

Keyword(s):

Impact Strength ◽

Sem Analysis ◽

Mass Ratio ◽

Polyamide 66 ◽

Scanning Calorimetry ◽

Elongation At Break ◽

Melt Compounding ◽

Twin Screw ◽

Ultra High Molecular Weight ◽

Comprehensive Property

By means of melt compounding method, the Glycidyl methacrylate (GMA) grafted HDPE modified Polyamide 66 (PA66) with ultra high molecular weight polyethylene (UHMWPE) blends were prepared via the co-rotating twin screw extruder．The effects of different UHMWPE/HDPE contents on properties of PA66/UHMWPE blends were investigated．Meanwhile, the mechanical properties such as tensile and impact strength etc. were investigated. By using the differential scanning calorimetry (DSC) and scanning electron microscope (SEM), the crystalline and morphology of PA66/UHMWPE blends were analyzed. The results show that UHMWPE toughened PA66 samples exhibit significantly enhanced impact strength and elongation at break comparison with natural PA66. The samples of PA66 with 30% of UHMWPE/HDPE (mass ratio 3/7) blends show impact strength about 2 times and elongation at yield 7 times more than those of natural PA66．The behavior of HDPE-g-GMA shows an effective compatibilizer for PA66/UHMWPE blends, when the mass ratio of PA66/(UHMWPE/HDPE) at 70:30, the blend indicates the best comprehensive property. The investigation on crystallization and morphology of PA66 and their blends show that the behaviors of melting about the two components are independent either PA66 or UHMWPE/HDPE. There are independent melting behaviors, meanwhile, interacted each other between PA66 and UHMWPE. Due to the good compatibility which HDPE-g-GMA contributed, the homogenous PA66/UHMWPE blends could be achieved. The photographs of SEM analysis indicate that the interface action of PA66 and polyethylene is enhanced by compatibilizer HDPE-g-GMA.

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Thermal and Thermomechanical Properties of Poly(butylene succinate) Nanocomposites

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.18231 ◽

2008 ◽

Vol 8 (4) ◽

pp. 1679-1689 ◽

Cited By ~ 1

Author(s):

Mamookho E. Makhatha ◽

Suprakas Sinha Ray ◽

Joseph Hato ◽

Adriaan S. Luyt

Keyword(s):

Thermal Stability ◽

Tensile Modulus ◽

Melting Behavior ◽

Mechanical Analysis ◽

Thermomechanical Properties ◽

Scanning Calorimetry ◽

Melt Mixing ◽

Butylene Succinate ◽

Modulated Differential Scanning Calorimetry ◽

Thermal Stability Of

This article describes the thermal and thermomechanical properties of poly(butylene succinate) (PBS) and its nanocomposites. PBS nanocomposites with three different weight ratios of organically modified synthetic fluorine mica (OMSFM) have been prepared by melt-mixing in a batch mixer at 140 °C. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) analyses and transmission electron microscopy (TEM) observations that reveal the homogeneous dispersion of the intercalated silicate layers into the PBS matrix. The thermal properties of pure PBS and the nanocomposite samples were studied by both conventional and temperature modulated differential scanning calorimetry (DSC) analyses, which show multiple melting behavior of the PBS matrix. The investigation of the thermomechanical properties was performed by dynamic mechanical analysis. Results reveal significant improvement in the storage modulus of neat PBS upon addition of OMSFM. The tensile modulus of neat PBS is also increased substantially with the addition of OMSFM, however, the strength at yield and elongation at break of neat PBS systematically decreases with the loading of OMSFM. The thermal stability of the nanocomposites compared to that of the pure polymer sample was examined under both pyrolytic and thermooxidative environments. It is shown that the thermal stability of PBS is increased moderately in the presence of 3 wt% of OMSFM, but there is no significant effect on further silicate loading in the oxidative environment. In the nitrogen environment, however, the thermal stability systematically decreases with increasing clay loading.

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Melt-Processed Poly(Ether Ether Ketone)/Carbon Nanotubes/Montmorillonite Nanocomposites with Enhanced Mechanical and Thermomechanical Properties

Materials ◽

10.3390/ma12030525 ◽

2019 ◽

Vol 12 (3) ◽

pp. 525 ◽

Cited By ~ 11

Author(s):

Ruixue Ma ◽

Bo Zhu ◽

Qianqian Zeng ◽

Pan Wang ◽

Yaming Wang ◽

...

Keyword(s):

Carbon Nanotubes ◽

Thermomechanical Properties ◽

Scanning Calorimetry ◽

Melt Mixing ◽

Maximum Increase ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Negative Effect ◽

Ether Ketone ◽

The Cost

The agglomeration problem of nanofillers, for instance, carbon nanotubes (CNTs) in a poly(ether ether ketone) (PEEK) matrix, is still a challenging assignment due to the intrinsic inert nature of PEEK to organic solvents. In this work, organically modified montmorillonite (MMT) was introduced as a second filler for improving the dispersion of CNTs in the PEEK matrix and enhancing the mechanical properties, as well as reducing the cost of the materials. The nanocomposites were fabricated through melt-mixing PEEK with CNTs/MMT hybrids, which were prepared in advance by mixing CNTs with MMT in water. The introduction of MMT improved the dispersion stability of CNTs, as characterized by sedimentation and zeta potential. The CNTs/MMT hybrids were maintained in PEEK nanocomposites as demonstrated by the transmission electron microscope. The mechanical and thermomechanical measurements revealed that CNTs together with MMT had a strong reinforcement effect on the PEEK matrix, especially at high temperature, although it had a negative effect on the toughness. A maximum increase of 48.1% was achieved in storage modulus of PEEK nanocomposites with 0.5 wt% CNTs and 2 wt% MMT at 240 °C, compared to that of neat PEEK. The differential scanning calorimetry results revealed that CNTs accelerated the crystallization of the PEEK matrix while a further addition of MMT played an opposite role. The nucleation activity of the fillers was also evaluated by the Dobreva method.

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Heat Treatment Effects on the Mechanical Properties and Morphologies of Poly (Lactic Acid)/Poly (Butylene Adipate-co-terephthalate) Blends

International Journal of Polymer Science ◽

10.1155/2013/951696 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 25

Author(s):

Hsien-Tang Chiu ◽

Szu-Yuan Huang ◽

Yan-Fu Chen ◽

Ming-Tai Kuo ◽

Tzong-Yiing Chiang ◽

...

Keyword(s):

Heat Treatment ◽

Lactic Acid ◽

Impact Strength ◽

Sem Analysis ◽

Poly Lactic Acid ◽

Scanning Calorimetry ◽

Two Phase ◽

Degree Of Crystallization ◽

High Degree ◽

Lower Tensile Strength

In this study the relationships between mechanicals properties and morphology of the poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends with or without heat treatment were investigated. The differential scanning calorimetry (DSC) analysis showed that blends have a two-phase structure indicating that they are immiscible. On the other hand, the PLA/PBAT (30/70) blend achieved the best tensile and impact strength because of its sea-island morphology, except for high PBAT content. The PLA/PBAT (70/30) and PLA/PBAT (50/50) blends showed irregular and directive-layer morphologies, in scanning electron microscopy (SEM) analysis, producing a break cross-section with various fiber shapes. Both blends showed lower tensile strength and impact strength than the PLA/PBAT (30/70). After heat treatment, the PLA/PBAT blends showed high modulus of tensile and HDT because of a high degree of crystallization. The high degree of crystallization in the blends, which originated in the heat treatment, reduced their impact strength and elongation. However, the effect of high degree of crystallization on the PLA/PBAT (30/70) blend was small because of its sea-island morphology.

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Poly(etheretherketone)/Poly(ethersulfone) Blends with Phenolphthalein: Miscibility, Thermomechanical Properties, Crystallization and Morphology

Polymers ◽

10.3390/polym13091466 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1466

Author(s):

Adrian Korycki ◽

Christian Garnier ◽

Amandine Abadie ◽

Valerie Nassiet ◽

Charles Tarek Sultan ◽

...

Keyword(s):

Differential Scanning Calorimetry ◽

Interfacial Adhesion ◽

Morphological Analysis ◽

Condensation Reaction ◽

Mechanical Analysis ◽

Thermomechanical Properties ◽

Glass Transitions ◽

Scanning Calorimetry ◽

Melt Mixing ◽

Spherical Domains

Polyetheretherketone (PEEK)/polyethersulfone (PES) blends are initially not miscible, except when the blends are prepared by solvent mixing. We propose a route to elaborate PEEK/PES blends with partial miscibility by melt mixing at 375 °C with phenolphthalein. The miscibility of blends has been examined using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMTA). When adding phenolphthalein to PEEK/PES blends, the glass transitions are shifted inward as an indication of miscibility. We suggest that phenolphthalein acts as a compatibilizer by creating cardo side groups on PEEK and PES chains by nucleophilic substitution in the melted state, although this condensation reaction was reported only in the solvent until now. In addition, phenolphthalein acts as a plasticizer for PES by decreasing its glass transition. As a consequence, the PEEK phase is softened which favors the crystallization as the increase of crystalline rate. Due to aromatic moieties in phenolphthalein, the storage modulus of blends in the glassy region is kept identical to pure PEEK. The morphological analysis by SEM pictures displays nano- to microsized PES spherical domains in the PEEK matrix with improved PEEK/PES interfacial adhesion.

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Thermomechanical Characterization of a Series of Crosslinked Poly[ethylene-co-(vinyl acetate)] (PEVA) Copolymers

MRS Proceedings ◽

10.1557/opl.2015.527 ◽

2015 ◽

Vol 1718 ◽

pp. 123-130 ◽

Cited By ~ 2

Author(s):

Matthias Heuchel ◽

Laith Al-Qaisi ◽

Karl Kratz ◽

Ulrich Nöchel ◽

Marc Behl ◽

...

Keyword(s):

Shape Memory ◽

Vinyl Acetate ◽

Mechanical Stability ◽

Shape Memory Polymer ◽

Thermomechanical Properties ◽

Scanning Calorimetry ◽

Temperature Range ◽

Shape Memory Effects ◽

Cross Links ◽

Poly Ethylene

ABSTRACTCrosslinked poly[ethylene-co-(vinyl acetate)] (cPEVA) has been recently introduced as a polymer material, which can be functionalized with various shape-memory effects by solely altering the thermomechanical treatment called programming.In this study two series of cPEVAs with different vinyl acetate contents of 18 wt% (cPEVA18) and 28 wt% (cPEVA28) comprising different crosslink densities were investigated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) in the temperature range of -130 °C to 120 °C. DMTA tests were performed in torsion mode, because such movements are highly relevant in the context of complex shape changes in shape-memory polymer based devices. Finally, the obtained DMTA results were compared with DMTA conducted in tension mode. Swelling experiments revealed a gel content in the range from 81% to 90% for cPEVA18 samples while for cPEVA28s a complete conversion was observed. The degree of swelling was found to decrease substantially with increasing crosslink density for both cPEVA series.The influence of VA content and extent of crosslinking on the appearance of the respective melting (Tm) and glass transition (Tg) as well as the thermomechanical properties of cPEVA systems could be demonstrated by discussing both DSC and DMTA results. The temperature range of mechanical stability correlates with the VA content and is determined by decreasing Tm values. The cross links do barely alter the stiffness of a PEVA up to the Tm rang, but lead to constant mechanical rigidity in the rubbery range above Tm.

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Effect of Dynamic Crosslinking on Mechanical Properties of PP/EPDM Blends

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19932642 ◽

1993 ◽

Vol 58 (11) ◽

pp. 2642-2650 ◽

Cited By ~ 10

Author(s):

Zdeněk Kruliš ◽

Ivan Fortelný ◽

Josef Kovář

Keyword(s):

Mechanical Properties ◽

Impact Strength ◽

Shear Modulus ◽

High Impact ◽

Necessary Condition ◽

Step Method ◽

Melt Mixing ◽

One Step ◽

High Impact Strength ◽

Dynamic Curing

The effect of dynamic curing of PP/EPDM blends with sulfur and thiuram disulfide systems on their mechanical properties was studied. The results were interpreted using the knowledge of the formation of phase structure in the blends during their melt mixing. It was shown, that a sufficiently slow curing reaction is necessary if a high impact strength is to be obtained. Only in such case, a fine and homogeneous dispersion of elastomer can be formed, which is the necessary condition for high impact strength of the blend. Using an inhibitor of curing in the system and a one-step method of dynamic curing leads to an increase in impact strength of blends. From the comparison of shear modulus and impact strength values, it follows that, at the stiffness, the dynamically cured blends have higher impact strength than the uncured ones.

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Mechanical Property Improvement of Poly(Butylene Succinate) by Reinforcing with Modified Fumed Silica

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.215 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 215-220 ◽

Cited By ~ 1

Author(s):

Sasirada Weerasunthorn ◽

Pranut Potiyaraj

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Impact Strength ◽

Flexural Strength ◽

Fumed Silica ◽

Tensile Modulus ◽

Silica Particles ◽

Melt Mixing ◽

Butylene Succinate ◽

Ir Spectrophotometry

Fumed silica particles (SiO2) were directly added into poly (butylene succinate) (PBS) by melt mixing process. The effects of amount of fumed silica particles on mechanical properties of PBS/fumed silica composites, those are tensile strength, tensile modulus, impact strength as well as flexural strength, were investigated. It was found that the mechanical properties decreased with increasing fumed silica loading (0-3 wt%). In order to increase polymer-filler interaction, fumed silica was treated with 3-glycidyloxypropyl trimethoxysilane (GPMS), and its structure was analyzed by FT-IR spectrophotometry. The PBS/modified was found to possess better tensile strength, tensile modulus, impact strength and flexural strength that those of PBS/fumed silica composites.

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Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block

Molecules ◽

10.3390/molecules26154705 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4705

Author(s):

Boer Liu ◽

Xi Chen ◽

Glenn A. Spiering ◽

Robert B. Moore ◽

Timothy E. Long

Keyword(s):

Hydrogen Bonding ◽

Self Assembly ◽

Microphase Separation ◽

Triblock Copolymers ◽

Random Copolymer ◽

Thermomechanical Properties ◽

Structure Property ◽

Scanning Calorimetry ◽

Central Block ◽

Quadruple Hydrogen Bonding

This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate (CyA) or post-functionalized ureido cytosine acrylate (UCyA) and the B unit consisted of n-butyl acrylate (nBA). Differential scanning calorimetry revealed two glass transition temperatures, suggesting microphase-separation in the A-AB-A triblock copolymers. Thermomechanical and morphological analysis revealed the effects of hydrogen bonding distribution and strength on the self-assembly and microphase-separated morphology. Dynamic mechanical analysis showed multiple tan delta (δ) transitions that correlated to chain relaxation and hydrogen bonding dissociation, further confirming the microphase-separated structure. In addition, UCyA triblock copolymers possessed an extended modulus plateau versus temperature compared to the CyA analogs due to the stronger association of quadruple hydrogen bonding. CyA triblock copolymers exhibited a cylindrical microphase-separated morphology according to small-angle X-ray scattering. In contrast, UCyA triblock copolymers lacked long-range ordering due to hydrogen bonding induced phase mixing. The incorporation of UCyA into the soft central block resulted in improved tensile strength, extensibility, and toughness compared to the AB random copolymer and A-B-A triblock copolymer comparisons. This study provides insight into the structure-property relationships of A-AB-A supramolecular triblock copolymers that result from tunable association strengths.

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Study of the Preparation and Properties of TPS/PBSA/PLA Biodegradable Composites

Journal of Composites Science ◽

10.3390/jcs5020048 ◽

2021 ◽

Vol 5 (2) ◽

pp. 48

Author(s):

Yuxuan Wang ◽

Yuke Zhong ◽

Qifeng Shi ◽

Sen Guo

Keyword(s):

Mechanical Properties ◽

Heat Resistance ◽

Thermoplastic Starch ◽

Sem Analysis ◽

Infrared Spectrometry ◽

Fourier Transform Infrared Spectrometry ◽

Melt Mixing ◽

Two Phase ◽

Biodegradable Composites ◽

Phase Compatibility

Thermoplastic starch/butyl glycol ester copolymer/polylactic acid (TPS/PBSA/PLA) biodegradable composites were prepared by melt-mixing. The structure, microstructure, mechanical properties and heat resistance of the TPS/PBSA/PLA composites were studied by Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), tensile test and thermogravimetry tests, respectively. The results showed that PBSA or PLA could bind to TPS by hydrogen bonding. SEM analysis showed that the composite represents an excellent dispersion and satisfied two-phase compatibility when the PLA, TPS and PBSA blended by a mass ration of 10, 30, and 60. The mechanical properties and the heat resistance of TPS/PBSA/PLA composite were improved by adding PLA with content less than 10%, according to the testing results.

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