scholarly journals Effect of Quinacridone Pigments on Properties and Morphology of Injection Molded Isotactic Polypropylene

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Mateusz Barczewski ◽  
Danuta Matykiewicz ◽  
Bartłomiej Hoffmann
Keyword(s):  
Isotactic Polypropylene ◽  
Morphological Changes ◽  
Hexagonal Phase ◽  
Impact Resistance ◽  
Polymeric Materials ◽  
Hardness Test ◽  
Thermomechanical Properties ◽  
Scanning Calorimetry ◽  
Nucleation Behavior ◽  
Injection Molded

Two quinacridone pigments were added (0.01; 0.05; 0.1; 0.5; 1; 2 wt%) to isotactic polypropylene (iPP), and their influence on mechanical and thermomechanical properties were investigated. Complex mechanical and thermomechanical iPP properties analyses, including static tensile test, Dynstat impact resistance measurement, and hardness test, as well as dynamic mechanic thermal analysis (DMTA), were realized in reference to morphological changes of polymeric materials. In order to understand the differences in modification efficiency and changes in polymorphism of polypropylene matrix caused by incorporation of pigments, differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) experiments were done. Both pigments acted as highly effective nucleating agents that influence morphology and mechanical properties of isotactic polypropylene injection molded samples. Differences between polypropylene samples nucleated by two pigments may be attributed to different heterogeneous nucleation behavior dependent on pigment type. As it was proved by WAXS investigations, the addition of γ-quinacridone (E5B) led to crystallization of polypropylene in hexagonal phase (β-iPP), while for β-quinacridone (ER 02) modified polypropylene no evidence of iPP β-phase was observed.

Application of dynamic mechanical analysis techniques to bismuth telluride based thermoelectric materials

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Witold Brostow ◽  
Kevin P. Menard ◽  
John B. White
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Bismuth Telluride ◽  
Polymeric Materials ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Tan Δ ◽  
Te Material

Abstract Dynamic mechanical analysis (DMA) techniques are commonly applied to characterize polymer-based materials - but little if at all to characterize semiconductor thermoelectric (TE) materials. TE materials may be coupled with polymeric materials in advanced thermoelectric devices, and the knowledge of TE material properties will be useful in the choice of materials for future applications. We have obtained DMA results for both n-type and p-type bismuth telluride based TE materials. We find that tan δ values, indicative of viscoelastic energy dissipation modes, approach the values for glassy or semi-crystalline polymers, and are larger by more than a whole order of magnitude than the tan δ of structural metals. DMA thermal scans show clear hysteresis-type effects and a correlation with differential scanning calorimetry thermal transitions. DMA properties as a function of frequency are briefly discussed. Our results show that DMA techniques are useful in the evaluation of thermophysical and thermomechanical properties of these TE materials and of assembled coolers. The viscoelastic effects we report may provide a damping mechanism for severe stresses inherent to service conditions of the TE coolers.

Influence of Crystal Structure on Thermo-Mechanical Properties of Injection Molded 𝛃-Nucleated iPP

2021 ◽  
Vol 36 (5) ◽  
pp. 545-556
Author(s):  
A. Hamza ◽  
R. K. Arya ◽  
A. D. Palsodkar ◽  
G. R. Bhadu ◽  
S. J. A. Rizvi
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Maleic Anhydride ◽  
Isotactic Polypropylene ◽  
Coupling Agent ◽  
Scanning Calorimetry ◽  
Slow Cooling ◽  
Melt Compounding ◽  
Crystal Fraction ◽  
Injection Molded

Abstract Isotactic polypropylene (iPP) was nucleated in-situ with calcium pimelate during melt compounding. Calcium pimelate is a highly effective β-nucleator for isotactic polypropylene (iPP). The β-nucleated iPP was characterized by wide angle x-ray diffraction (WAXD) and differential scanning calorimetry (DSC) for its crystallinity and crystal structure. In addition, the injection-molded samples were tested for thermo-mechanical properties. It is found that very low quantity (< 0.1 wt. %) of β-nucleator is required to produce sufficiently high β-crystal fraction (Kβ) in isotactic polypropylene. β-nucleated iPP shows increment of 11 to 14 °C in its heat deflection temperature (HDT). It was also observed that slow cooling rate of β-nucleated iPP promotes the formation of β-crystals and that tensile stretching leads to complete transformation of β crystals into a-crystals at room temperature. It was also revealed that the presence of maleic anhydride grafted polypropylene (PP-g-MA), a well-known coupling agent (or compatibilizer), may reduce the (Kβ) value to a marginal extent. It was also observed that the thermo-mechanical properties were not much affected by the presence of PP-g-MA. Therefore, calcium pimelate may be used as β-nucleator in case of neat as well as reinforced polypropylene containing maleic anhydride as coupling agent.

Melting, Crystallization Behaviors and Mechanical Properties of iPP Nucleated by β Nucleation Masterbatches

2014 ◽  
Vol 941-944 ◽  
pp. 1229-1232
Author(s):  
Guo Rui Dou ◽  
Qiang Dou
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Impact Strength ◽  
Isotactic Polypropylene ◽  
Tensile Strain ◽  
Mechanical Tests ◽  
Crystalline Form ◽  
Scanning Calorimetry ◽  
Crystallization Behaviors ◽  
Injection Molded

Injection-molded β-isotactic polypropylene (β-iPP) specimens were prepared by adding three β nucleation masterbatches, i.e., NT-MA, NT-MB and NT-MC, respectively. The melting, crystallization and mechanical properties of β-iPP specimens were investigated by means of differential scanning calorimetry (DSC) and mechanical tests. It is revealed that β crystalline form contents were enhanced by the β nucleation masterbatches, and the β contents of the cores were higher than those of the skins of injection molded specimens. The tensile strain at break and Izod notched impact strength of iPP were greatly improved by the β nucleation masterbatches. It was found that the β nucleation efficiency was in the order: NT-MC > NT-MA > NT-MB.

scholarly journals Poly(Acrylonitrile–Butadiene–Styrene) as a Special β-Nucleating Agent on the Toughness of Isotactic Polypropylene

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1894
Author(s):  
Jingru Liu ◽  
Xinxu Zhu ◽  
Zheng Cao
Keyword(s):  
Isotactic Polypropylene ◽  
Acrylonitrile Butadiene Styrene ◽  
Nucleating Agent ◽  
Scanning Calorimetry ◽  
Molding Method ◽  
Stress Transmission ◽  
Injection Molded ◽  
The Impact ◽  
Poly Acrylonitrile ◽  
Butadiene Styrene

The influence of poly(acrylonitrile–butadiene–styrene) (ABS) as a special β-nucleating agent on the impact and tensile properties of isotactic polypropylene (iPP) were investigated by dynamic rheological measurements, wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and mechanical properties tests. It is found that the β nucleation efficiency of ABS is closely related to its concentration, dispersibility, and molding method for the iPP/ABS blends. The content of β-crystal (Kβ) rises with the incorporation of ABS and shows a maximum with the introduction of 1% ABS for compression-molded blends and 2% ABS for injection-molded blends, respectively, which is followed by a decrease in Kβ. The addition of a small amount of ABS has a significant reinforcing and toughening effect on iPP. Compared with the compression-molded samples, the ABS dispersed phase in injection-molded samples has a smaller particle size and a larger specific surface area, which are favorable for stress transmission and higher β nucleation efficiency, and therefore, better tensile and impact properties can be expected.

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

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 890
Author(s):  
Mateusz Barczewski ◽  
Olga Mysiukiewicz ◽  
Aleksander Hejna ◽  
Radosław Biskup ◽  
Joanna Szulc ◽  
...  
Keyword(s):  
Impact Strength ◽  
Mechanical Stability ◽  
Thermomechanical Analysis ◽  
Thermomechanical Properties ◽  
Phenyl Isocyanate ◽  
Sem Analysis ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Expanded Vermiculite ◽  
Chain Extenders

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.

scholarly journals Proof-of-Concept of Detection of Counterfeit Medicine through Polymeric Materials Analysis of Plastics Packaging

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2185
Author(s):  
Mohammad Salim ◽  
Riyanto Teguh Widodo ◽  
Mohamed Ibrahim Noordin
Keyword(s):  
Polymeric Materials ◽  
Proof Of Concept ◽  
Scanning Calorimetry ◽  
Counterfeit Drug ◽  
Drug Products ◽  
Counterfeit Medicines ◽  
Counterfeit Medicine ◽  
Counterfeit Pharmaceuticals ◽  
Purge Gas ◽  
Sample Set

The detection of counterfeit pharmaceuticals is always a major challenge, but the early detection of counterfeit medicine in a country will reduce the fatal risk among consumers. Technically, fast laboratory testing is vital to develop an effective surveillance and monitoring system of counterfeit medicines. This study proposed the combination of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Differential Scanning Calorimetry (DSC) for the quick detection of counterfeit medicines, through the polymer analysis of blister packaging materials. A sample set containing three sets of original and counterfeit medicine was analyzed using ATR-FTIR and DSC, while the spectra from ATR-FTIR were employed as a fingerprint for the polymer characterization. Intending to analyze the polymeric material of each sample, DSC was set at a heating rate of 10 °C min−l and within a temperature range of 0- 400 °C, with nitrogen as a purge gas at a flow rate of 20 ml min−an. The ATR-FTIR spectra revealed the chemical characteristics of the plastic packaging of fake and original medicines. Further analysis of the counterfeit medicine’s packaging with DSC exhibited a distinct difference from the original due to the composition of polymers in the packaging material used. Overall, this study confirmed that the rapid analysis of polymeric materials through ATR-FTIR and comparing DSC thermograms of the plastic in their packaging effectively distinguished counterfeit drug products.

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

Molecules ◽  
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.

scholarly journals Laboratory Study of the Ultraviolet Radiation Effect on an HDPE Geomembrane

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 390
Author(s):  
Fernando Luiz Lavoie ◽  
Marcelo Kobelnik ◽  
Clever Aparecido Valentin ◽  
Érica Fernanda da Silva Tirelli ◽  
Maria de Lurdes Lopes ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Morphological Changes ◽  
Field Performance ◽  
Melt Flow Index ◽  
Flow Index ◽  
Test Results ◽  
Upward Trend ◽  
Scanning Calorimetry ◽  
Ultraviolet Exposure ◽  
Brittle Behavior

High-density polyethylene (HDPE) geomembranes are polymeric geosynthetic materials usually applied as a liner in environmental facilities due to their good mechanical properties, good welding conditions, and excellent chemical resistance. A geomembrane’s field performance is affected by different conditions and exposures, including ultraviolet radiation, thermal and oxidative exposure, and chemical contact. This article presents an experimental study with a 1.0 mm-thick HDPE virgin geomembrane exposed by the Xenon arc weatherometer for 2160 h and the ultraviolet fluorescent weatherometer for 8760 h to understand the geomembrane’s behavior under ultraviolet exposure. The evaluation was performed using the melt flow index (MFI) test, oxidative-induction time (OIT) tests, tensile test, differential scanning calorimetry (DSC) analysis, and Fourier transform infrared spectroscopy (FTIR) analysis. The sample exposed in the Xenon arc equipment showed a tendency to increase the MFI values during the exposure time. This upward trend may indicate morphological changes in the polymer. The tensile behavior analysis showed a tendency of the sample to lose ductility, without showing brittle behavior. The samples’ OIT test results under both device exposures showed faster antioxidant depletion for the standard OIT test than the high-pressure OIT test. The DSC and FTIR analyses did not demonstrate the polymer’s changes.

scholarly journals Nucleating agents based on graphene and graphene oxide for crystallization of the β-form of isotactic polypropylene

2019 ◽  
Vol 55 (4) ◽  
pp. 1436-1450 ◽  
Author(s):  
Jan Broda ◽  
Marcin Baczek ◽  
Janusz Fabia ◽  
Dorota Binias ◽  
Ryszard Fryczkowski
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Isotactic Polypropylene ◽  
Reduced Form ◽  
Pimelic Acid ◽  
Nucleating Agents ◽  
Scanning Calorimetry ◽  
Functionalized Graphene Oxide ◽  
Reduced Graphene ◽  
Carboxylic Groups

Abstract During the investigations, functionalization of graphene oxide synthesized using modified Hummers’ method and its reduced form was performed. Mixtures of graphene oxide and reduced graphene oxide with pimelic acid and calcium hydroxide were prepared for functionalization. During the reaction, the molecules of pimelic acid were attached to the surface of graphene sheets. By forming links between the carboxylic groups of pimelic acid and graphene oxide, the durable connection was achieved. The functionalized graphene oxide and the reduced graphene oxide were used as additives in isotactic polypropylene crystallization. The influence of additives on crystallisation in non-isothermal conditions was examined using polarized optical microscopy and differential scanning calorimetry. The effect of the additives on the polypropylene structure was analysed using wide-angle X-ray scattering. For both functionalized compounds, the nucleating ability towards β-form of polypropylene was detected. Both additives showed the increase in the nucleation rate and promotion of growth of the β-form crystals. Nucleation efficiency similar to other nucleating agents used in the crystallization of the β-form of polypropylene was revealed.

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