Use of Benzene-1,3-Bis(Sulfonyl)Azide as Crosslinking Agent of TPVs Based on EPDM Rubber—Polyolefin Blends

2001 ◽  
Vol 74 (2) ◽  
pp. 198-210 ◽  
Author(s):  
Miguel A. López Manchado ◽  
José M. Kenny†
Keyword(s):  
Crosslinking Agent ◽  
Thermal Characterization ◽  
Chain Scission ◽  
Dynamic Vulcanization ◽  
Polyolefin Blends ◽  
Thermoplastic Matrix ◽  
Sulfonyl Azide ◽  
Preliminary Study ◽  
Ethylene Propylene Diene Terpolymer ◽  
Vulcanization Process

Abstract The use of innovative crosslinking agents for the preparation of thermoplastic vulcanizates (TPVs) is investigated. In this preliminary study, the most common TPV systems, based on polypropylene (iPP) and ethylene—propylene—diene terpolymer rubber (EPDM) blends, are studied. Among typical vulcanization agents, only the peroxides are able to crosslink saturated elastomers, however, they present the disadvantage that give rise to chain scission of the thermoplastic matrix. For this reason, the main goal of the present study is to investigate a new vulcanization agent for elastomeric matrices, which also permit the dynamic vulcanization process in their blends with polyolefins. This agent is based on a diazide derivative, benzene-1,3-bis(sulfonyl)azide that, for the specific behavior of the sulfonyl azide group, allows its interaction with the carbon—hydrogen bonds of the elastomeric phase and of the polyolefin. The study includes the dynamic vulcanization of PP—EPDM blends and their rheological, mechanical and thermal characterization. A comparison with traditional TPVs prepared with sulfur as vulcanization agent is also presented.

New Developments in Dynamically Cured PP—EPDM Blends

2001 ◽  
Vol 74 (2) ◽  
pp. 211-220 ◽  
Author(s):  
Miguel A. López-Manchado ◽  
Miguel Arroyo ◽  
José M. Kenny
Keyword(s):  
Mechanical Properties ◽  
Crosslinking Agent ◽  
Three Dimensional ◽  
Mechanical Analysis ◽  
Dynamic Vulcanization ◽  
New Developments ◽  
Dimensional Network ◽  
Polymeric Chains ◽  
Ethylene Propylene Diene Terpolymer ◽  
Vulcanization Process

Abstract Different procedures for preparing thermoplastic vulcanizates (TPVs), based on isotactic polypropylene (iPP) and ethylene—propylene—diene terpolymer rubber (EPDM), are used and analyzed in this work. In order to determine the effect of the vulcanization method on material properties, a rheological study, dynamic-mechanical analysis, mechanical properties and morphological study have been carried out. In all cases, the sulfur is used as crosslinking agent of the elastomeric phase. It has been shown that the dynamically cured blends (referred in the work as V2 and V3) present better properties in relation to those statically cured (V1) and uncrosslinked (V). Thus, the elastic ability, mechanical properties and rheological characteristics of these systems sensibly increase when the samples are dynamically vulcanized. Morphological analysis performed by scanning electron microscopy (SEM) is clearly in agreement with the analyzed properties, showing a better dispersion between both polymeric chains, when the blends are dynamically cured. These results seem to indicate that the dynamic vulcanization process gives rise to the formation of a thermally stable three-dimensional network, and as a consequence of it, a sensible increase of the properties is obtained.

scholarly journals The effect of polyhedral oligomeric silsesquioxanes (POSSs) incorporation in ethylene-propylene-diene-terpolymer (EPDM): a thermal study

2021 ◽  
Author(s):  
Ignazio Blanco ◽  
Traian Zaharescu
Keyword(s):  
Room Temperature ◽  
Thermal Characterization ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Dsc Analysis ◽  
Γ Irradiation ◽  
Scanning Calorimetry ◽  
Ethylene Propylene ◽  
Oligomeric Silsesquioxane ◽  
Ethylene Propylene Diene Terpolymer ◽  
Dynamic Heating

AbstractA series of ethylene-propylene-diene-terpolymer (EPDM)/polyhedral oligomeric silsesquioxane (POSS) composites at different percentage of POSS were prepared and subjected to γ-irradiation. Both irradiated and non-irradiated EPDM and composites were investigated by the means of thermal analysis to verify if the presence of POSS molecules is able to reduce the oxidation level of free radicals generated during the degradation and to evaluate the effects of the irradiation. EPDM composites at 1, 3 and 5 mass% of POSS were thus degraded in a thermogravimetric (TG) balance in dynamic heating conditions (25–700 °C), in both inert and oxidative atmosphere by flowing nitrogen and air respectively. Thermal characterization was then completed by carrying out Differential Scanning Calorimetry (DSC) analysis from sub-ambient to better highlight the melting of the polymer and polymer composites occurring just above the room temperature. FTIR spectroscopy was also performed for the prepared samples to check the presence of the molecular filler in the composites and for the TG’s residue at 700 °C, in order to evaluate its nature. DSC and TGA parameters were detected and discussed to have information about the effect of the degradation’s environment, the effect of irradiation on polymer stabilization and the effect of POSS content in the polymer matrix.

Influence of Multifunctional Monomers on Gamma Irradiated Polylactic Acid

2015 ◽  
Vol 804 ◽  
pp. 59-62 ◽  
Author(s):  
Kantima Chaochanchaikul ◽  
Wanlop Harnnarongchai
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polylactic Acid ◽  
Irradiation Dose ◽  
Crosslinking Agent ◽  
Chain Scission ◽  
Chain Extension ◽  
Molecular Characteristics ◽  
High Irradiation Dose ◽  
Gamma Irradiated

The aim of this work was to compare and discuss the influence of multifunctional monomers as crosslinking agent (Triallyl Isocyanurate; TAIC) and chain extender (Joncryl ADR4368) on the gamma irradiated Polylactic acid (PLA). The modified PLA samples with varying amount of TAIC and Joncryl were characterized by observing the molecular characteristics and mechanical properties. The results showed that irradiated PLA had lower average molar mass and mechanical properties compared to non-irradiated PLA due to irradiation induced chain scission. Gel content was observed and increased with increasing irradiation dose for the TAIC modified sample, indicating that the further crosslink of irradiated PLA was occurring. Crosslinking and chain extension were responsible for the improved modulus and tensile strength of irradiated PLA, however the decrease in tensile strength at high irradiation dose was observed for crosslinked PLA.

Stress Relaxation Studies of Scission in Rubber Vulcanizates

1960 ◽  
Vol 33 (1) ◽  
pp. 72-77
Author(s):  
A. Mercurio ◽  
A. V. Tobolsky
Keyword(s):  
Stress Relaxation ◽  
Main Chain ◽  
Crosslinking Agent ◽  
Chain Structure ◽  
Air Atmosphere ◽  
Diffusion Effects ◽  
Relaxation Experiments ◽  
Prime Objective ◽  
The Common ◽  
Vulcanization Process

Abstract Deterioration of many vulcanized hydrocarbon rubbers is known to be due to reaction with molecular oxygen. Such a process is independent of oxygen concentration down to several mm of oxygen pressure and hence proceeds quite readily in an air atmosphere provided that experiments are conducted with thin enough samples to eliminate oxygen diffusion effects. Two chemically distinct loci for attack by oxygen are available. These are the crosslinked sites which are added during the vulcanization process and the network chains which are essentially the same as in the unvulcanized material. The prime objective of this study is to show clearly that vulcanized natural rubber suffers oxidative scission predominantly along the polyisoprene chains and not at the crosslinked sites as proposed by Berry and Watson. Other literature has appeared which indicates that this important point needs further clarification. Stress relaxation experiments, which measure the rate of breaking of the weakest chemical bonds recurring throughout the structure, have been utilized. If the crosslinks are oxidized, then similar rates of scission should be obtained for different chain structures so long as the common crosslink is present in all of them. On the other hand, if chains are oxidized, then rates of scission should be essentially independent of the crosslinking agent used but rather depend markedly on each chain structure. The five chain structures used in this study are depicted in Table I. In each case at least a few per cent of double bond-containing segments are present in the main chain to allow for ordinary chemical vulcanization methods. All of these have been crosslinked by sulfur and by a nonsulfur containing agent.

Preparation of polyoxymethylene/methyl vinyl silicone rubber/thermoplastic polyurethane ternary thermoplastics vulcanizates with good toughness properties

2021 ◽  
pp. 089270572110571
Author(s):  
Wei Fang ◽  
Xiaodong Fan ◽  
Ruilong Li
Keyword(s):  
Silicone Rubber ◽  
Thermoplastic Polyurethane ◽  
Mechanical Tests ◽  
Curing Agent ◽  
Dynamic Vulcanization ◽  
Elongation At Break ◽  
Methyl Vinyl ◽  
Thermoplastic Vulcanizates ◽  
Vulcanization Process ◽  
Batch Mixer

Novel thermoplastic vulcanizates (TPVs) based on polyoxymethylene (POM) and methyl vinyl silicone rubber (MVQ) have been prepared by dynamic vulcanization process through a batch mixer. During the preparation of TPV blends, Di-(tert butyl peroxyisopropyl) benzene (BIBP) was used as the curing agent in order to make MVQ cross-linked and TPU was used to coat MVQ for improving the compatibility of MVQ and POM. In order to understand the influence of different compositions on TPV blends, five groups of experimental processes were described in detail. During these experiments, the amount of POM was reduced from 70phr to 30phr, that of MVQ was gradually increased from 18phr to 42 phr, and TPU was increased from 12phr to 28phr. In addition, the morphology and properties of TPVs were studied by DSC, FTIR, SEM, DMA and mechanical tests. The mechanical testing results showed that with the amount of POM decreasing and the total amount of MVQ and TPU increasing, the tensile strength of the TPV blends gradually was decreased, and the elongation at break was increased accordingly from 35.2 ± 6% of pure POM to 142.8 ± 11% of sample 5#.

scholarly journals TPV: A New Insight on the Rubber Morphology and Mechanic/Elastic Properties

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2315
Author(s):  
Cindy Le Hel ◽  
Véronique Bounor-Legaré ◽  
Mathilde Catherin ◽  
Antoine Lucas ◽  
Anthony Thèvenon ◽  
...  
Keyword(s):  
Carbon Black ◽  
Crosslinking Agent ◽  
Domain Size ◽  
Organic Peroxide ◽  
Packing Fraction ◽  
Crosslinking Reaction ◽  
High Concentration ◽  
Compression Set ◽  
Thermoplastic Matrix ◽  
Rubber Phase

The objective of this work is to study the influence of the ratio between the elastomer (EPDM) phase and the thermoplastic phase (PP) in thermoplastic vulcanizates (TPVs) as well as the associated morphology of the compression set of the material. First, from a study of the literature, it is concluded that the rubber phase must be dispersed with a large distribution of the domain size in the thermoplastic phase in order to achieve a high concentration, i.e., a maximal packing fraction close to ~0.80. From this discussion, it is inferred that a certain degree of progress in the crosslinking reaction must be reached when the thermoplastic phase is melted during mixing in order to achieve dispersion of the elastomeric phase in the thermoplastic matrix under maximum stress. In terms of elasticity recovery which is measured from the compression set experiment, it is observed that the crosslinking agent nature (DCP or phenolic resin) has no influence in the case of a TPV compared with a pure crosslinked EPDM system. Then, the TPV morphology and the rubber phase concentration are the first order parameters in the compression set of TPVs. Finally, the addition of carbon black fillers leads to an improvement of the mechanical properties at break for the low PP concentration (20%). However, the localization of carbon black depends on the crosslinking chemistry nature. With radical chemistry by organic peroxide decomposition, carbon black is located at the interface of EPDM and PP acting as a compatibilizer.

The Effects of Trans-Polyoctene Rubber and Dynamic Vulcanization on Properties of PP/EPDM/NR Blends

2005 ◽  
Vol 21 (1) ◽  
pp. 39-53 ◽  
Author(s):  
H. Ismail Halimatuddahliana ◽  
H. Md. Akil
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Good Adhesion ◽  
Dynamic Vulcanization ◽  
Blend Ratio ◽  
Elongation At Break ◽  
Oil Resistance ◽  
Morphological Studies ◽  
Opposite Trend ◽  
Ethylene Propylene Diene Terpolymer

The effects of trans-polyoctene rubber (TOR) and dynamic vulcanization on the processability, tensile properties, oil resistance and morphology of unvulcanized and vulcanized polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/ natural rubber (NR) blends were investigated. The highest stabilization torque was obtained with vulcanized PP/EPDM/NR blends containing TOR, followed by control blends and unvulcanized blends containing TOR. At a similar blend ratio the tensile strength and the stress at 100% elongation of vulcanized PP/ EPDM/NR blends containing TOR were again higher than those of unvulcanized blends containing TOR and of the control blends. However, the opposite trend was observed with respect to elongation at break, whereby vulcanized PP/EPDM/NR blend had the lowest values The oil resistance of unvulcanized and vulcanized blends containing TOR was greater than that of the control blends. From morphological studies, it is clear that the incorporation of TOR in unvulcanized and vulcanized PP/EPDM/NR blends improved the homogeneity and promoted good adhesion between phases.

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