Rubber-Thermoplastic Compositions. Part VIII. Nitrile Rubber Polyolefin Blends with Technological Compatibilization

1983 ◽  
Vol 56 (5) ◽  
pp. 1045-1060 ◽  
Author(s):  
A. Y. Coran ◽  
R. Patel
Keyword(s):  
Block Copolymer ◽  
Graft Copolymer ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Melt Mixing ◽  
Dynamic Vulcanization ◽  
Oil Resistance ◽  
Polyolefin Blends ◽  
Thermoplastic Vulcanizates

Abstract The results of this work suggest a practical route to hot-oil-resistant thermoplastic elastomers based on NBR and a polyolefin resin (such as polypropylene). Although these two types of polymer are normally grossly incompatible with each other, a melt-mixed blend thereof is technologically improved by the presence of a small amount of a compatibilizing block copolymer which contains both polar and nonpolar segments. Ideally, the block copolymer should contain molecular segments of the types of polymers to be compatibilized. The compatibilizing block (graft) copolymer can form in situ during melt-mixing. Dynamic vulcanization (during melt-mixing) of a compatibilized NBR-polypropylene blend produces a thermoplastic elastomer with mechanical properties about as good as those of a corresponding composition of EPDM and polypropylene (two polymers which are nearly mutually compatible in a thermodynamic sense). The compatibilizing NBR-polypropylene graft copolymer might act by reducing (molten-state) interfacial tension at the NBR-polypropylene interface and also by increasing the interfacial adhesion in the “solidified-state” composition during its use. The hot-oil resistance of the compatibilized NBR-polypropylene thermoplastic vulcanizates is excellent. Also, the NBR-polypropylene compositions can be blended with thermoplastic vulcanizates based on EPDM and polypropylene to obtain thermoplastic elastomeric compositions which exhibit both good hot oil resistance and low temperature brittleness characteristics.

Structure-Property Relationships of Poly(Butylene Terephthalate)/Polyolefin Blends

1998 ◽  
Vol 18 (1-2) ◽  
pp. 17-30 ◽  
Author(s):  
D.S. Lee ◽  
J.K. Doo ◽  
B. Kim ◽  
J. Kim
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Structure Property ◽  
Melt Mixing ◽  
Butylene Terephthalate ◽  
Polyolefin Blends ◽  
Structure Property Relationships ◽  
Acrylic Ester ◽  
Discrete Phase

Abstract Structure-property relationships of poly(butylene terephthalate) (PBT) / polyolefin (PO) (80/20) blends modified by a reactive compatibilizer, ethylene-acrylic ester-glycidyl methacrylate terpolymer (BAG), were investigated as part of studies on toughening of PBT. POs used for the study were ethylene propylene rubber (EPR), low-density polyethylene (LDPE), and high-density polyethylene (HDPE), whose deformabilities were different at room temperature. It was observed that the particle size of PO in the discrete phase was the smallest when the EAG content was 8~12 wL%. Shear viscosity of the blends increased as the particle size was decreased. It seems that the morphology and rheological properties of the blends were affected by graft copolymers formed in situ from EAG and PBT during melt mixing. Brittle-tough transition of impact strength of the PBT/EPR/EAG blends was observed when the EAG content was increased from 0 to 4 wt% at room temperature. However, blends of PBT/LDPE/EAG and PBT/HDPE/EAG showed brittle-tough transition with increasing the EAG content from 8 wt% to 12 wt%. It is postulated that toughening of the PBT depends on the deformability of the discrete PO particle as well as its size.

scholarly journals Thermoplastic elastomers containing 2D nanofillers: montmorillonite, graphene nanoplatelets and oxidized graphene platelets

2015 ◽  
Vol 17 (4) ◽  
pp. 74-81 ◽  
Author(s):  
Sandra Paszkiewicz ◽  
Iwona Pawelec ◽  
Anna Szymczyk ◽  
Zbigniew Rosłaniec
Keyword(s):  
Tensile Modulus ◽  
Thermoplastic Elastomer ◽  
Tensile Tests ◽  
Thermoplastic Elastomers ◽  
Graphene Nanoplatelets ◽  
Soft Phase ◽  
Permanent Set ◽  
Transmission Electron ◽  
Tetramethylene Oxide

Abstract This paper presents a comparative study on which type of platelets nanofiller, organic or inorganic, will affect the properties of thermoplastic elastomer matrix in the stronger manner. Therefore, poly(trimethylene terephthalate-block-poly(tetramethylene oxide) copolymer (PTT-PTMO) based nanocomposites with 0.5 wt.% of clay (MMT), graphene nanoplatelets (GNP) and graphene oxide (GO) have been prepared by in situ polymerization. The structure of the nanocomposites was characterized by transmission electron microscopy (TEM) in order to present good dispersion without large aggregates. It was indicated that PTT-PTMO/GNP composite shows the highest crystallization temperature. Unlike the addition of GNP and GO, the introduction of MMT does not have great effect on the glass transition temperature of PTMO-rich soft phase. An addition of all three types of nanoplatelets in the nanocomposites caused the enhancement in tensile modulus and yield stress. Additionally, the cyclic tensile tests showed that prepared nanocomposites have values of permanent set slightly higher than neat PTT-PTMO.

scholarly journals The Microstructure of GNR and the Mechanical Properties of Biobased PLA/GNR Thermoplastic Vulcanizates with Excellent Toughness

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 294 ◽  
Author(s):  
Mingfeng Xia ◽  
Wenchao Lang ◽  
Yue Yang ◽  
Jihang Yu ◽  
Ningjing Wu ◽  
...  
Keyword(s):  
Glycidyl Methacrylate ◽  
Crosslinking Density ◽  
Poly Lactic Acid ◽  
Dynamic Vulcanization ◽  
Melt Grafting ◽  
Thermoplastic Vulcanizates ◽  
Grafting Reactions ◽  
Graft Yield ◽  
The Impact

A series of different contents of glycidyl methacrylate (GMA)-grafted natural rubber (GNR) copolymers were fabricated via green bulk melt-grafting reactions, and super-tough bio-based poly (lactic acid) (PLA)/GNR thermoplastic vulcanizates (TPVs) were achieved by in-situ dynamic vulcanization. Increasing the graft yield, gel fraction, and crosslinking density of GNR vulcanizates effectively improved the ductility of the PLA/GNR TPVs, while prolonging the dynamic vulcanization time and increasing the GMA graft yield led to a notable enhancement in the impact toughness of the PLA/GNR TPVs. PLA/30 wt % GNR TPVs exhibited a significantly increased elongation (410%) and notched impact strength (73.2 kJ/m2), which were 40 and 15 times higher than those of the PLA/30 wt % NR TPVs, respectively. The new bio-based PLA/GNR TPVs offer promise as replacements for petroleum-based polymers in the automotive, 3D printing, and packaging fields.

Rubber-Thermoplastic Compositions. Part IX. Blends of Dissimilar Rubbers and Plastics with Technological Compatibilization

1985 ◽  
Vol 58 (5) ◽  
pp. 1014-1023 ◽  
Author(s):  
A. Y. Coran ◽  
R. Patel ◽  
D. Williams-Headd
Keyword(s):  
Mechanical Properties ◽  
Block Copolymers ◽  
Melt Mixing ◽  
Thermoplastic Vulcanizate ◽  
Vulcanized Rubber ◽  
Rubber Particles ◽  
Thermoplastic Vulcanizates ◽  
Compatibilizing Agent

Abstract From this work, one can conclude that compositions which have excellent mechanical properties can be prepared by melt-mixing thermoplastic vulcanizates. (A thermoplastic vulcanizate is a composition containing vulcanized rubber particles dispersed in a thermoplastic. Such a composition is usually prepared by vulcanizing the rubber during its melt-mixing with a thermoplastic.) The excellent mixed TPV compositions can be obtained even though the rubbers and plastics are mutually grossly incompatible with respect to thermodynamic considerations. In such cases, however, it appears to be necessary that a compatibilizing agent be present in the mixture to promote the interaction between the thermoplastic materials. Block copolymers whose molecules contain blocks common to each of the thermoplastic blend components are good technological compatibilizing agents (e.g., polypropylene-nylon block copolymers to compatibilize mixtures containing polypropylene and nylon). Compatibilizing block copolymers can form in situ during melt mixing. This appears to be the case when one of the thermoplastic blend components is functionalized to chemically link with another thermoplastic component of the mixed TPV composition. The rubber associated with one thermoplastic can differ greatly from the rubber associated with another thermoplastic component of the mixed TPV blend. Thus, a composition which has good mechanical properties can contain both differing thermoplastics and differing rubbers. As a result, the possible combinations of components for TPV compositions has been greatly expanded.

Effect of Sulfur Donor on Properties of Thermoplastic Vulcanizates Based on NR/PP

2012 ◽  
Vol 626 ◽  
pp. 54-57 ◽  
Author(s):  
Chanida Manleh ◽  
Charoen Nakason ◽  
Natinee Lopattananon ◽  
Azizon Kaesaman
Keyword(s):  
Storage Modulus ◽  
Crosslink Density ◽  
Dynamic Properties ◽  
Complex Viscosity ◽  
Melt Mixing ◽  
Dynamic Vulcanization ◽  
Thermoplastic Vulcanizates ◽  
Pp Blends ◽  
Thermal Stability Of ◽  
Sulfur Donor

Thermoplastic vulcanizates based on natural rubber and polypropylene blend (NR/PP) was prepared via dynamic vulcanization by melt mixing process at 180°C and a rotor speed of 60 rpm. Three types of vulcanizing agent (i.e., Tetramethyl thiuram disulfide (TMTD), 4,4 Dithiodimorpholine (DTDM) and Dipentamethylene thiuram tetrasulfide (Tetrone A)) were used to cure the rubber phase of NR/PP blends. Influence loading levels of sulfur donor at 1, 2 and 3 phr on dynamic properties and crosslink density were studied. The result showed that the dynamically cured NR/PP blends with Tetrone A gave higher mechanical properties, storage modulus, complex viscosity, and crosslink density with the lower value of tanδ than those of the blends with TMTD and DTDM. Furthermore, the storage modulus, complex viscosity and crosslink density of TPVs increased with increasing loading levels for all types of sulfur donor. It was also found that thermal stability of dynamically cured NR/PP blends is higher than that of the pure NR.

Side Chain Liquid Crystalline Thermoplastic Elastomers for Actuator and Electromechanical Applications

2005 ◽  
Vol 889 ◽  
Author(s):  
Eric Verploegen ◽  
LaRuth C. McAfee ◽  
Lu Tian ◽  
Darren Verploegen ◽  
Paula T. Hammond
Keyword(s):  
Block Copolymer ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Liquid Crystalline Phase ◽  
Transverse Orientation ◽  
Isotropic Liquid ◽  
Polymer Backbone ◽  
Spacer Length

ABSTRACTThe synthesis of a polystyrene-b-polyvinylmethylsiloxane-b-polystyrene diblock and triblock copolymer functionalized with liquid crystals exhibiting a smectic C* phase on the PVMS central block is described. The synthetic route is based on the anionic polymerization of styrene and trimethyltrivinylsiloxane monomers and the functionalization of resulting triblock copolymers. The resulting polymer can self assemble into a thermoplastic elastomer where the high Tg styrene blocks serve as physical crosslinks for a low Tg siloxane block. The presence of a smectic liquid crystalline phase and the block copolymer mesophase are observed across various temperature ranges depending on the length of the spacer connecting the liquid crystalline moiety to the polymer backbone. The influence of mechanical deformation upon the morphologies of the liquid crystalline and block copolymer mesophases was investigated. The interactions between the smectic LC and the block copolymer morphologies and their influence upon their respective orientations in response to shear fields are detailed. The parallel-transverse orientation of the hexagonally close packed (HCP) cylinders of the block copolymer morphology and the smectic liquid crystalline phase, respectively, was observed for melt fiber drawn samples. However, the transverse-perpendicular orientation was observed for liquid crystalline block copolymers that experienced oscillatory shear. The transverse orientation of HCP cylinders was observed while shearing took place above the smectic to isotropic transition temperature, indicating that the presence of an isotropic liquid crystalline phase alters the orientation of the block copolymer morphology. Additionally, it was found that the spacer length was a key factor in the clearing points for the smectic liquid crystalline phase, as well as significantly influencing the nanophase segregation of the block copolymer.

Translucent Thermoplastic Elastomers

2009 ◽  
Vol 82 (1) ◽  
pp. 94-103
Author(s):  
Maria D. Ellul ◽  
D. R. Hazelton
Keyword(s):  
Thermal Stability ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
New Materials ◽  
Dynamic Vulcanization ◽  
Ethylene Propylene ◽  
Fluid Delivery ◽  
Compression Set ◽  
Ethylene Content

Abstract Thermoplastic elastomer vulcanizates, TPVs, having the property of optical translucence have been prepared by dynamic vulcanization. The new materials are based on a polypropylene homopolymer principally containing propylene units of exactly alternating configuration and having a syndiotactic pentad fraction of at least 0.86. The dispersed elastomer phase consists of a crosslinked ethylene propylene copolymer rubber having an ethylene content of at least 74 weight %. These thermoplastic elastomer compositions have significantly lowered Gardner haze values, while maintaining the desirable properties of low compression set and thermal stability. The compositions have utility in molded mechanical rubber goods as well as extruded articles for fluid delivery applications.

Rubber-Thermoplastic Compositions. Part V. Selecting Polymers for Thermoplastic Vulcanizates

1982 ◽  
Vol 55 (1) ◽  
pp. 116-136 ◽  
Author(s):  
A. Y. Coran ◽  
R. P. Patel ◽  
D. Williams
Keyword(s):  
Plastic Material ◽  
Elastic Recovery ◽  
Melt Mixing ◽  
Dynamic Vulcanization ◽  
Entanglement Density ◽  
Surface Energies ◽  
Molecular Length ◽  
Thermoplastic Vulcanizates ◽  
Plastic Components ◽  
Critical Chain

Abstract Based on a few characteristics of the pure rubber and plastic components, rubber-plastic combinations can be selected, with a high probability of success, to give thermoplastic vulcanizates (by dynamic vulcanization) of good mechanical integrity and elastic recovery. The characteristics used in the selection are estimated surface energies, crystallinity of the hard phase (plastic) material and the critical chain length, of the rubber molecules, for entanglement. The best compositions are prepared when the surface energies of the rubber and plastic material are matched, when the entanglement molecular length of the rubber is low (high entanglement density) and when the plastic material is crystalline. Of course, it is required that neither the plastic, nor the rubber decompose in the presence of the other at temperatures required for melt mixing. Also, a curing system is required, appropriate for the rubber under the conditions of melt-mixing.

Novel Styrenic Thermoplastic Elastomers from Blends with Special Reference to Compatibilization and Dynamic Vulcanization

2005 ◽  
Vol 78 (5) ◽  
pp. 893-909 ◽  
Author(s):  
J. D. Patel ◽  
M. Maiti ◽  
K. Naskar ◽  
Anil K. Bhowmick
Keyword(s):  
Special Reference ◽  
Interaction Parameter ◽  
Functional Performance ◽  
Thermoplastic Elastomer ◽  
Thermoplastic Elastomers ◽  
Dynamic Vulcanization ◽  
Vulcanized Rubber ◽  
Styrene Acrylonitrile ◽  
Modified Polystyrene ◽  
Styrene Butadiene

Abstract A thermoplastic elastomer (TPE) is a rubbery material with final properties and functional performance similar to those of a conventional vulcanized rubber at ambient temperature, yet it can be processed in a molten condition as a thermoplastic polymer at elevated temperature. The main objectives of the present investigation are: to prepare novel styrenic-based thermoplastic elastomers based on blends of a thermoplastic (polystyrene or styrene acrylonitrile) with a rubber (styrene butadiene or ethylene vinylacetate) and to investigate the interaction between various polymers with special reference to compatibilization via oxazoline-modified polystyrene or oxazoline-modified styrene acrylonitrile and dynamic vulcanization. Styrene acrylonitrile/ethylene vinylacetate blends are found to exhibit better overall properties, especially tensile strength, elongation at break and tension set. The solubility or interaction parameter and the morphology of the blends are the key parameters, which basically govern the final properties of blends. Physical properties of these blends have been correlated with the interaction parameter and final morphology.

PREPARATION AND CHARACTERIZATION OF HNBR/PA12-BASED SUPER TPVs WITH ENHANCED THERMAL STABILITY BY USING HIGHER ACRYLONITRILE CONTENT

2018 ◽  
Vol 91 (2) ◽  
pp. 357-374 ◽  
Author(s):  
Syed Ismail Syed Mohammed Reffai ◽  
Kinsuk Naskar
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
High Performance ◽  
Service Condition ◽  
High Heat ◽  
Mechanical Analysis ◽  
Thermoplastic Elastomers ◽  
Butadiene Rubber ◽  
Melt Mixing ◽  
Dynamic Vulcanization

ABSTRACT Thermoplastic vulcanizates (TPVs) are superior classes of thermoplastic elastomers, in which dynamic vulcanization of the rubber phase takes place during melt mixing with a semicrystalline thermoplastic matrix phase at elevated temperature. TPV is characterized by processing behaviors like thermoplasticity at elevated temperature and performance properties of vulcanized rubber at ambient temperature. High-performance TPVs or super TPVs are new-generation TPVs that exhibit high heat resistance as well as excellent oil resistance properties suitable for under-the-hood automotive applications. In the present work, a new class of super TPVs based on hydrogenated acrylonitrile–butadiene rubber (HNBR) and polyamide (PA12) has been developed. TPVs of three different acrylonitrile content (ACN)–based fixed-blend ratio (70:30) of (HNBR/PA12) have been prepared by using a peroxide curative {Di-(2-tert-butyl peroxy isopropyl) benzene (DTBPIB)}. Final morphology of TPVs varies depending on the ACN content of the rubber. A TPV with the highest ACN content shows the highest level of mechanical properties as well as superior thermal stability and creep behavior compared with all other TPVs. Dynamic mechanical analysis also demonstrates that the tan δ values of all the TPVs are lower and the storage moduli are higher than the low acrylonitrile content system. Heat aging, oil aging, oil swelling, and network characterization studies have also been carried out in detail to understand the performance behavior of these super TPVs at service condition (150 °C). These TPVs are considered for potential applications in the automotive sector, especially for under-the-hood-applications.

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