scholarly journals Effect of the Elongational Flow on the Morphology and Properties of Polymer Systems: A Brief Review

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3529
Author(s):  
Rossella Arrigo ◽  
Giulio Malucelli ◽  
Francesco Paolo La Mantia
Keyword(s):  
Rheological Properties ◽  
Polymer Melt ◽  
Elongational Flow ◽  
Polymer Processing ◽  
Industrial Applications ◽  
Fiber Spinning ◽  
Polymer Systems ◽  
Great Relevance ◽  
Elongation Flow ◽  
Structure Properties

Polymer-processing operations with dominating elongational flow have a great relevance, especially in several relevant industrial applications. Film blowing, fiber spinning and foaming are some examples in which the polymer melt is subjected to elongational flow during processing. To gain a thorough knowledge of the material-processing behavior, the evaluation of the rheological properties of the polymers experiencing this kind of flow is fundamental. This paper reviews the main achievements regarding the processing-structure-properties relationships of polymer-based materials processed through different operations with dominating elongational flow. In particular, after a brief discussion on the theoretical features associated with the elongational flow and the differences with other flow regimes, the attention is focused on the rheological properties in elongation of the most industrially relevant polymers. Finally, the evolution of the morphology of homogeneous polymers, as well as of multiphase polymer-based systems, such as blends and micro- and nano-composites, subjected to the elongational flow is discussed, highlighting the potential and the unique characteristics of the processing operations based on elongation flow, as compared to their shear-dominated counterparts.

Physical Microfabrication of Shape-Memory Polymer Systems via Bicomponent Fiber Spinning

2016 ◽  
Vol 37 (22) ◽  
pp. 1837-1843 ◽  
Author(s):  
Syamal S. Tallury ◽  
Behnam Pourdeyhimi ◽  
Melissa A. Pasquinelli ◽  
Richard J. Spontak
Keyword(s):  
Shape Memory ◽  
Shape Memory Polymer ◽  
Fiber Spinning ◽  
Polymer Systems ◽  
Bicomponent Fiber

scholarly journals Broadband Dielectric Spectroscopy Study of Biobased Poly(alkylene 2,5-furanoate)s’ Molecular Dynamics

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1355 ◽  
Author(s):  
Michelina Soccio ◽  
Daniel E. Martínez-Tong ◽  
Giulia Guidotti ◽  
Beatriz Robles-Hernández ◽  
Andrea Munari ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Dielectric Spectroscopy ◽  
Relaxation Times ◽  
Barrier Properties ◽  
Polymer Processing ◽  
Industrial Applications ◽  
Structure Property ◽  
Property Relations ◽  
Broadband Dielectric Spectroscopy ◽  
Segmental Relaxation

Poly(2,5-alkylene furanoate)s are bio-based, smart, and innovative polymers that are considered the most promising materials to replace oil-based plastics. These polymers can be synthesized using ecofriendly approaches, starting from renewable sources, and result into final products with properties comparable and even better than those presented by their terephthalic counterparts. In this work, we present the molecular dynamics of four 100% bio-based poly(alkylene 2,5-furanoate)s, using broadband dielectric spectroscopy measurements that covered a wide temperature and frequency range. We unveiled complex local relaxations, characterized by the simultaneous presence of two components, which were dependent on thermal treatment. The segmental relaxation showed relaxation times and strengths depending on the glycolic subunit length, which were furthermore confirmed by high-frequency experiments in the molten region of the polymers. Our results allowed determining structure–property relations that are able to provide further understanding about the excellent barrier properties of poly(alkylene 2,5-furanoate)s. In addition, we provide results of high industrial interest during polymer processing for possible industrial applications of poly(alkylene furanoate)s.

scholarly journals Synthesis of SiC Based Fibers with Continuous Pore Structure by Melt- Spinning and Controlled Curing Method

2009 ◽  
Vol 66 ◽  
pp. 5-8 ◽  
Author(s):  
Kenichiro Kita ◽  
Masaki Narisawa ◽  
Hiroshi Mabuchi ◽  
Masayoshi Itoh ◽  
Masaki Sugimoto ◽  
...  
Keyword(s):  
Pore Structure ◽  
Melt Spinning ◽  
Polymer Melt ◽  
Fiber Spinning ◽  
Hydrogen Gas ◽  
Structure Control ◽  
Gas Source ◽  
Pore Structures ◽  
Curing Method ◽  
The Individual

Silicon carbide (SiC) based fibers with continuous pore structures were synthesized by the precursor method using a polycarbosilane (PCS) and polymethylhydrosiloxane (PMHS) polymer blends. The pore formation process can be explained by hydrogen gas dissolution in the polymer melt and desaturation process of the dissolved gas during the fiber spinning. We investigated the effect of PMHS additives with different chemical and physical natures on the obtained pore structures, because PMHS decomposition process played a role of hydrogen gas source. The individual polymer melts were characterized by viscosity measurement, gas chromatograph analysis and thermogravimetric (TG) analysis in order to obtain details of pore structure control.

Product Strength and Orientation Manipulation via Vibration-Assisted Injection Molding

2002 ◽  
Author(s):  
David C. Angstadt ◽  
John P. Coulter
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Injection Molding ◽  
Molecular Orientation ◽  
Polymer Melt ◽  
Polymer Processing ◽  
Shear Yielding ◽  
Processing Methods ◽  
Improve Product

This investigation focuses on determining why polystyrene ASTM specimens exhibit an increase in tensile strength when processed by vibration assisted injection molding (VAIM) while polycarbonate parts do not. VAIM is one of several polymer processing methods that attempt to improve product properties via manipulation of the polymer melt. Observation of birefringence patterns in VAIM processed polystyrene samples show a significant impact on molecular orientation. The same studies were conducted on opaque polycarbonate and were unable to determine the degree of molecular orientation via birefringence measurement. It was theorized that VAIM did not produce significant orientation due to its higher thermal conductivity and stiffer backbone. It has been determined by this investigation that VAIM processing does impart significant molecular orientation in polycarbonate specimens but still does not increase its UTS. It is proposed that increased molecular orientation induced by VAIM processing inhibits crazes from growing into cracks. VAIM therefore favors polymers that fail by crazing (e.g., polystyrene) rather than those that fail by shear yielding (e.g., polycarbonate).

scholarly journals A Comprehensive Approach from Interfacial to Bulk Properties of Legume Protein-Stabilized Emulsions

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 65 ◽  
Author(s):  
Manuel Félix ◽  
Alberto Romero ◽  
Cecilio Carrera-Sanchez ◽  
Antonio Guerrero
Keyword(s):  
Rheological Properties ◽  
Size Distribution ◽  
Droplet Size ◽  
Electrostatic Interactions ◽  
Ph Value ◽  
Droplet Size Distribution ◽  
Interfacial Properties ◽  
Industrial Applications ◽  
Droplet Sizes ◽  
Legume Protein

The correlation between interfacial properties and emulsion microstructure is a topic of special interest that has many industrial applications. This study deals with the comparison between the rheological properties of oil-water interfaces with adsorbed proteins from legumes (chickpea or faba bean) and the properties of the emulsions using them as the only emulsifier, both at microscopic (droplet size distribution) and macroscopic level (linear viscoelasticity). Two different pH values (2.5 and 7.5) were studied as a function of storage time. Interfaces were characterized by means of dilatational and interfacial shear rheology measurements. Subsequently, the microstructure of the final emulsions obtained was evaluated thorough droplet size distribution (DSD), light scattering and rheological measurements. Results obtained evidenced that pH value has a strong influence on interfacial properties and emulsion microstructure. The best interfacial results were obtained for the lower pH value using chickpea protein, which also corresponded to smaller droplet sizes, higher viscoelastic moduli, and higher emulsion stability. Thus, results put forward the relevance of the interfacial tension values, the adsorption kinetics, the viscoelastic properties of the interfacial film, and the electrostatic interactions among droplets, which depend on pH and the type of protein, on the microstructure, rheological properties, and stability of legume protein-stabilized emulsions.

Characterization, Modification and Rheology of Green Clay

2015 ◽  
Vol 820 ◽  
pp. 60-64
Author(s):  
Leila Verônica da Rocha-Gomes ◽  
Antônio José Santana ◽  
Camila Martini Matos ◽  
Valquíria de Fátima Justo ◽  
Maria Das Graças Silva-Valenzuela ◽  
...  
Keyword(s):  
Water Absorption ◽  
Rheological Properties ◽  
Apparent Density ◽  
Industrial Applications ◽  
Clay Sample ◽  
Oil Drilling ◽  
Smectite Clays ◽  
Swelling Capacity ◽  
Before And After ◽  
Green Clay

Smectite clays or bentonites are used in several industrial applications. The aim of this study was to describe the characterization and organophilization of a green clay sample coming from the State of Paraíba, Brazil. The clay was characterized by XRD, XRF, CEC, SEM, stereoscopic microscopy, Fann viscosity (before and after the organophilization process), swelling capacity in water and some organic solvents. Prismatic specimens were conformed by pressing, for which were conformed the mechanical sthegth after drying at 110°C and after burning at 950°C. The burned specimens were analyzed to evaluate dimensional variations, water absorption, apparent porosity and apparent density. XRD showed that the sample was constituted mainly for montmorillonite claymineral. Analysis of rheological properties of the modified clay indicates its potential to meet the specifications of the standard N-2604 of Petrobras, concerning clays used to oil drilling.

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