Effect of Architecture on the Properties of Polyisobutylene-Based TPE Materials

2007 ◽  
Vol 80 (4) ◽  
pp. 661-671 ◽  
Author(s):  
Judit E. Puskas ◽  
Lucas M. Dos Santos ◽  
Mustafa Y. Sen ◽  
Gabor Kaszas
Keyword(s):  
Molecular Weight ◽  
First Generation ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Polymeric Coating ◽  
Unique Combination ◽  
Design And Synthesis ◽  
Drug Eluting ◽  
Surface Modified ◽  
Number Of Branches

Abstract This paper will discuss the design and synthesis of polyisobutylene-based thermoplastic elastomers (TPEs) for biomedical and other specialty applications. The first generation from this class of polymers, linear triblock polystyrene-b-polyisobutylene-b-polystyrene (PSt-b-PIB-b-PSt or SIBS), is FDA-approved and currently used as the polymeric coating on drug-eluting coronary stents. TPEs with arborescent (dendritic) polyisobutylene core (arbPIB-b-PSt) the third generation, display unique combination of properties. Our latest results include the synthesis of surface-modified TPEs. This paper will give a short overview of the effect of architecture (number of branches, molecular weight and size) on select properties of arbPIB-based TPEs. It will be demonstrated that block copolymers with a high molecular weight dendritic (arborescent) polyisobutylene core and poly(para-methylstyrene) end blocks can manifest themselves either as a rubber, or as a plastic, depending on their environment. The behavior is thermally irreversible. We called this material the “chameleon thermoplastic elastomer.” This material represents a new concept in material science: ETPE (entropy-driven thermoplastic elastomer).

The Mechanical Properties of a Thermoplastic Elastomer Produced by the Bacterium Pseudomonas oleovorans

1992 ◽  
Vol 65 (4) ◽  
pp. 761-777 ◽  
Author(s):  
K. D. Gagnon ◽  
R. W. Lenz ◽  
R. J. Farris ◽  
R. C. Fuller
Keyword(s):  
Molecular Weight ◽  
Thermoplastic Elastomer ◽  
Stationary Growth Phase ◽  
Thermoplastic Elastomers ◽  
Decomposition Temperature ◽  
Polymer Composition ◽  
Growth Time ◽  
Pseudomonas Oleovorans ◽  
Permanent Strain ◽  
Chemical Structures

Abstract PHO, a poly(β-hydroxyalkanoate) copolymer containing mostly β-hydroxyoctanoate repeating units, was produced in a fed batch fermentation process by Pseudomonas oleovorans when grown on sodium octanoate as the sole carbon source. The polymer from different batches—evaluated with regards to composition, molecular weight distribution, thermal transition temperatures, and decomposition temperature—was found to be highly consistent batch-to-batch. Polymer composition as a function of growth time did not change significantly once the culture reached the stationary growth phase. PHO when crystallized at room temperature from the melt, forms a physically crosslinked network with the crystalline regions acting as the physical crosslinks. The molecular weight between physical crosslinks was determined to be approximately 4000. The stress-strain properties, hardness, and tensile set of PHO were found to be within the range of values defined by a variety of commercially available thermoplastic elastomers with differing chemical structures. The tensile set of PHO was high, 35% after 100% elongation. Experimental evidence supports three possible sources of the high tensile set: permanent strain-induced orientation or displacement of the physical crosslinks, irreversible strain-induced crystallization, and deformation-induced changes of the size and purity/perfection of crystalline regions.

scholarly journals RELAXATION PROPERTIES OF COMPOSITE MATERIALS BASED ON MIXTURES OF EPOXY POLYMERS AND THERMOPLASTIC ELASTOMERS

2020 ◽  
pp. 85-95
Author(s):  
Y. Kochergin ◽  
Tatyana Grigorenko ◽  
V. Zolotareva
Keyword(s):  
Molecular Weight ◽  
High Temperature ◽  
Block Copolymers ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Relaxation Processes ◽  
Polybutylene Terephthalate ◽  
Dynamic Mechanical ◽  
Epoxy Polymers ◽  
Polytetramethylene Oxide

The influence of thermoplastic elastomers, which are two-block statistical block copolymers based on polybutylene terephthalate and polytetramethylene oxide with a different ratio of rigid and elastic blocks, on the static and dynamic mechanical properties of epoxy polymers is studied. The initial compounds for the synthesis of block copolymers are dimethyl terephthalate, 1,4-butanediol and polytetramethylenoxide with a molecular weight of 2000. The tetrabutoxide is used as catalyst. The process of interaction of the initial components is carried out in two stages, the reaction of transesterification and copolycondensation is consistently carried out. The composition of BSP is set by the ratio of initial reagents. The total molecular weight of block copolymers is 30–40 thousand. The method of dynamic mechanical analysis shows that the introduction of modifiers leads to a decrease in molecular mobility in a wide temperature range from low-temperature (at 220K) to high-temperature (at 380K) relaxation transitions. The magnitude of the effect depends on the ratio of rigid and flexible blocks in the block copolymer. It is assumed that the decrease in the tangent of the angle of mechanical losses at temperatures below the glass transition temperature and especially in the region of the β-transition, may be associated with the slowdown of relaxation processes at the interface of the epoxide matrix with rigid blocks of thermoplastic elastomer. The observed effects in the region of high-temperature transition may be associated with the restriction of freedom of conformational rearrangements near the interface of the epoxy polymer with polybutylene terephthalate and polytetramethylene oxide blocks and an increase in the cross-linking density of the epoxy. A noticeable decrease in the magnitude and creep rate of epoxy composites is found when thermoelastoplast is introduced.

scholarly journals Studies on PBFMO-b-PNMMO alternative block thermoplastic elastomers as potential binders for solid propellants

RSC Advances ◽  
2019 ◽  
Vol 9 (51) ◽  
pp. 29765-29771 ◽  
Author(s):  
Minghui Xu ◽  
Xianming Lu ◽  
Hongchang Mo ◽  
Ning Liu ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Solid Propellants ◽  
Polymeric Binder

A novel energetic polymeric binder PBFMO-b-PNMMO alternative block thermoplastic elastomer was developed for metal-rich solid propellants.

scholarly journals Properties and Structure of Concretes Doped with Production Waste of Thermoplastic Elastomers from the Production of Car Floor Mats

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 872
Author(s):  
Malgorzata Ulewicz ◽  
Alina Pietrzak
Keyword(s):  
Tensile Strength ◽  
Production Process ◽  
Compression Strength ◽  
Physical And Mechanical Properties ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Production Waste ◽  
Fine Aggregate ◽  
Freezing And Thawing ◽  
Average Decrease

This article presents physical and mechanical properties of concrete composites that include waste thermoplastic elastomer (TPE) from the production process of car floor mats. Waste elastomer (2–8 mm fraction) was used as a substitute for fine aggregate in quantities of 2.5, 5.0, 7.5, and 10% of the cement weight. For all series of concrete, the following tests were carried out: compression strength, bending tensile strength, splitting tensile strength, absorbability, density, resistance to water penetration under pressure, frost resistance, and abrasion resistance, according to applicable standards. Moreover, SEM/EDS analysis was carried out on the surface microstructure of synthesized concrete composites. It was proven that the use of production waste from the production process of car floor mats in the quantity of 2.5% does not influence the change of the concrete microstructure and it does not result in the decrease of the mechanical parameters of concrete modified with waste. All concrete modified with the addition of waste meet standards requirements after carrying out 15 cycles of freezing and thawing, and the average decrease in compression strength did not exceed 20%. Adding waste in the quantity of 2.5% allows for limiting the use of aggregate by about 5%, which is beneficial for the natural environment.

scholarly journals Effect of Acetylated SEBS/PP for Potential HVDC Cable Insulation

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1596
Author(s):  
Peng Zhang ◽  
Yongqi Zhang ◽  
Xuan Wang ◽  
Jiaming Yang ◽  
Wenbin Han
Keyword(s):  
Mechanical Properties ◽  
Field Strength ◽  
Thermoplastic Elastomer ◽  
High Energy ◽  
Thermoplastic Elastomers ◽  
Electrical Strength ◽  
Voltage Stabilizer ◽  
Breakdown Field ◽  
Cable Insulation ◽  
Breakdown Field Strength

Blending thermoplastic elastomers into polypropylene (PP) can make it have great potential for high-voltage direct current (HVDC) cable insulation by improving its toughness. However, when a large amount of thermoplastic elastomer is blended, the electrical strength of PP will be decreased consequently, which cannot meet the electrical requirements of HVDC cables. To solve this problem, in this paper, the inherent structure of thermoplastic elastomer SEBS was used to construct acetophenone structural units on its benzene ring through Friedel–Crafts acylation, making it a voltage stabilizer that can enhance the electrical strength of the polymer. The DC electrical insulation properties and mechanical properties of acetylated SEBS (Ac-SEBS)/PP were investigated in this paper. The results showed that by doping 30% Ac-SEBS into PP, the acetophenone structural unit on Ac-SEBS remarkably increased the DC breakdown field strength of SEBS/PP by absorbing high-energy electrons. When the degree of acetylation reached 4.6%, the DC breakdown field strength of Ac-SEBS/ PP increased by 22.4% and was a little higher than that of PP. Ac-SEBS, with high electron affinity, is also able to reduce carrier mobility through electron capture, resulting in lower conductivity currents in SEBS/PP and suppressing space charge accumulation to a certain extent, which enhances the insulation properties. Besides, the highly flexible Ac-SEBS can maintain the toughening effect of SEBS, resulting in a remarkable increase in the tensile strength and elongation at the break of PP. Therefore, Ac-SEBS/PP blends possess excellent insulation properties and mechanical properties simultaneously, which are promising as insulation materials for HVDC cables.

Elastomeric Polycarbonate Block Copolymers

1965 ◽  
Vol 38 (2) ◽  
pp. 431-449
Author(s):  
Eugene P. Goldberg
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Bisphenol A ◽  
Flexural Modulus ◽  
Softening Temperature ◽  
Thermoplastic Elastomers ◽  
Partial Replacement ◽  
Initial Increase ◽  
Copolymer Composition ◽  
Moderate Degree

Abstract Polycarbonate block copolymers were prepared by phosgenating pyridine solutions of polyether glycol-bisphenol-A mixtures. Copolycarbonates derived from poly(oxyethylene) glycols (Carbowaxes) were studied in detail for property-structure effects as a function of glycol molecular weight (1000–20,000) and copolymer composition (5–70 weight per cent or 0.3–10.0 mole per cent of a 4000 molecular weight glycol). Remarkable strength (>7000 psi) and snappy elasticity (>90 per cent immediate recovery) were observed at poly(oxyethylene) block concentrations greater than 3 mole per cent. These thermoplastic elastomers also exhibited high softening temperatures (>180° C) and tensile elongations up to about 700 per cent. Both Tg and softening temperature varied linearly with comonomer mole ratio over the composition range studied, with Tg displaying much greater polyether concentration sensitivity. It is suggested that the observed property effects result to a large extent from the variation in poly(bisphenol-A carbonate) block length that accompanies the changing of copolymer composition. An initial increase in flexural modulus (stiffness) was observed at low polyether concentrations (0–1 mole per cent). This phenomenon is considered to be related to similar modulus effects found in plasticized rigid thermoplastics at low plasticizer concentrations. A moderate degree of molecular order, due to bisphenol carbonate segments rather than the normally crystalline polyether, was detected by x-ray analysis. Elastomeric carbonate-carboxylate tetrapolymers were also prepared by partial replacement of carbonate with isophthalate, terephthalate or adipate linkages in polyether-bisphenol systems. The dramatic softening temperature depression observed in this class of polymers is attributed to the disruption of long bisphenol carbonate block sequences that exist in the simpler polyether glycol-bisphenol carbonate copolymers.

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