Ethylidene Norbornene Research Articles

Multidisciplinary design of door inner belt weatherstrip for simultaneous reduction of wind noise and squeaking in electric vehicles

In electric vehicles (EVs), addressing noise, vibration, and harshness (NVH) has become pivotal, especially concerning external wind noise. To reduce wind noise, a door inner belt weatherstrip needs a high contact load, but this can lead to squeaking noise at the glass/weatherstrip interface. This study demonstrates a multidisciplinary design for the weatherstrip to tackle both issues. By increasing ethylene propylene diene monomer and ethylidene norbornene contents in the thermoplastic vulcanizate (TPV) by about 20 % and 70 %, respectively, the compression set was reduced from 35.4 % to 27.6 %. Concurrently, the TPV’s damping properties improved, with a 25 % increase in loss modulus (323 MPa). Coated flocking surface of weatherstrip significantly reduced the friction coefficient by 80 % (from 1.75 to 0.30). In vehicle evaluations, the newly designed weatherstrip reduced the wind noise by 5 dB(A) and eliminated. This approach highlights the potential of multidisciplinary design in optimizing NVH for next-generation vehicles, including autonomous EVs and urban air mobility.

The preparation of polyolefin elastomer functionalized with polysiloxane and its effect in ethylene-propylene-diene monomer/silicon rubber blends

The functionalization of polyolefin elastomer with polysiloxane can prepare novel elastomer with great compatibility, antifouling property, thermal stability and dielectricity. Herein, norbornene-derived polysiloxane was synthesized by anionic ring-opening polymerization of hexamethylcyclotrisiloxane (D3) and further used in terpolymerization with ethylene and cyclodiolefin (ethylidene norbornene or dicyclopentadiene) to prepare polysiloxane-functionalized polyolefin elastomer. High polymerization activity was obtained using vanadium-based Ziegler-Natta catalyst, and the terpolymer exhibited high polysiloxane content and Mn, which respectively reach as high as 8.5 mol% and 176.6 kg/mol. The introduction of cyclodiolefin into terpolymer could increase molecular weight, regulate crystallinity and provide reactive sites, especially ethylidene norbornene. With the polysiloxane content in terpolymer increasing, terpolymers transformed from thermoplastic to elastomer and showed better elasticity. The polysiloxane-functionalized polyolefin elastomer (Silo-70) was subsequently added into ethylene-propylene-diene monomer (EPDM)/silicone rubber (SR) blend to prepare high-performance composite. After the addition of 2 phr Silo-70, the blend showed the tensile strength and elongation at break respectively at 11.5 MPa and 878%, comparable to EPDM rubber, and the initial decomposition temperature (T5) significantly increased from 410.0 to 456.3 °C. The better miscibility between EPDM and SR was verified from DMA and SEM results.

Mill Processability, Rheology and Structure Differences of Polyacrylate Elastomers

Abstract Two commercial polyacrylate elastomers, one having epoxide (EP) crosslinking sites and the other ethylidene norbornene (ENB) were selected. It was demonstrated that the former was more difficult to mill-process than the latter. The viscoelastic properties measured at very small strain in shear oscillation indicated that the ENB polymer was more branched than the EP polymer. The gel determination by filteration confirmed this. The tensile stress-strain measurements were conducted at four different deformation rates. These data were treated according to the strain-time correspondence principle to see if this principle applies to the data of these samples. The data of EP polymer did not form a master curve, thus, the above principle is not applicable; at the larger deformation the strain-hardening tendencies were observed. This indicates that the EP polymer has a rather extensive long branching, a type of which usually results from a chain transfer reaction. The data of the ENB polymer, on the other hand, form a master-curve; that is, the strain-time correspondence principle is applicable, in spite of the presence of the large amount of gel. This means that the gel in the ENB polymer is microgel. The micro-gel in this case is polymer-latex particle, crosslinked during emulsion polymerization with a difunctional comonomer. Thus, in this work polymer rheology was effectively used to find a major difference in the polymer chain structure. In this way it was shown that the results of polymerization may be related to mill processability.

Synthesis of bromine‐functionalized polyolefins by scandium‐catalyzed copolymerization of 10‐bromo‐1‐decene with ethylene, propylene, and dienes

By use of a THF‐containing trimethylsilylmethyl scandium catalyst system (C5Me4SiMe3)Sc(CH2SiMe3)2(THF)/[Ph3C][B(C6F5)4], the multi‐component copolymerization of 10‐bromo‐1‐decene (BrDC) with ethylene, propylene, and dienes has been achieved to afford a new family of bromine‐functionalized polyolefins with controllable composition and high molecular weight. The copolymerization of BrDC with ethylene afforded the well‐defined BrDC–ethylene copolymers with high BrDC incorporation (up to 12 mol%) and high molecular weight (Mw > 100 kg mol−1). The terpolymerization of propylene, ethylene with BrDC afforded random ethylene–propylene–BrDC terpolymers with controllable bromine content (2 ~ 11 mol%), high molecular weight (Mw > 100 kg mol−1) and low glass transition temperature (Tg = −51 °C ~ −67 °C). Moreover, the tetrapolymerization of ethylene, propylene, BrDC, and ethylidene norbornene or conjugated dienes such as isoprene and myrcene has been achieved for the first time to afford selectively the bromine‐functionalized ethylene–propylene–diene rubbers containing various types of double bonds.

Occupational Exposure Limits for ethylidene norbornene, ethyleneimine, benomyl, and 2,3-epoxypropyl methacrylate, and classifications on carcinogenicity.

Occupational Exposure Limits for ethylidene norbornene, ethyleneimine, benomyl, and 2,3-epoxypropyl methacrylate, and classifications on carcinogenicity.

Tuning the properties of α,ω-bis(trialkoxysilyl) telechelic copolyolefins from ruthenium-catalyzed chain-transfer ring-opening metathesis polymerization (ROMP)

Low viscosity liquid α,ω-bis(trialkoxysilyl) telechelic copolyolefins are reported.

РАЗРАБОТКА ПОЛИМЕРНЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ НА ОСНОВЕ ТЕРМОПЛАСТИЧНЫХ ЭЛАСТОМЕРОВ

This paper presents data on the development of polymer composite materials based on thermoplastic elastomers. As starting materials for the synthesis of the matrix components were selected as follows: isotactic polypropylene and ternary ethylene-propylene-diene elastomer (EPDM). Diene component in EPDM are ethylidene norbornene composition in an amount of 4-5%. Dynamic vulcanization was carried out using the elastomer element sulfur. The filler polymer composite materials used silica gel with dimethyl polysiloxane. Synthesis was carried out by filling the sol-gel technology. The filler content in the composite varied from 10 to 80% by weight. Mixing of filler and the matrix was performed in a laboratory twin-rotor mixer, type "Brabender". It is found that the maximum possible filler content of the matrix used was 80%. With the introduction of more filler mixing of the components it has been difficult. When the filler content from 10 to 70% of parameters such as tensile strength, flexural strength and modulus of longitudinal elasticity increasing and administered at higher filler and 80 wt%. markedly reduced. Thus, it can be concluded that the content of filler in the composite is 70%. Further research should be directed to the evaluation of the radiation resistance of the developed composite materials.

Influence of molecular structure of blend components on the performance of thermoplastic vulcanisates prepared by electron induced reactive processing

Polypropylene (PP)/ethylene propylene diene rubber (EPDM) thermoplastic vulcanisates (TPVs) were prepared by electron induced reactive processing without use of any chemical vulcanizing agent, co-agent or other type of additive. Thus, the composition of PP/EPDM blend is not changed by this novel process and relationships between raw material, process, morphology and properties of TPVs can be studied in a simple way. Consequently, the molecular mass of PP as well as the amount and nature of diene (ethylidene norbornene or vinyl norbornene) were varied. Based on detailed mechanical, dynamic mechanical, morphological, thermal and rheological investigations as well as equilibrium solvent swelling measurements and sol–gel analyses it was found that molecular mass, amount and nature of diene influence the cross-linking efficiency. In addition, the use of low molecular mass blend components leads to PP-EPDM phase graft-links as well as increased values of elongation and tensile strength at break.

Developing ethylene-propylene-diene rubber compounds for industrial applications using a sulfur-bearing silanized silica nanofiller

The loading of a sulfur-bearing silanized silica nanofiller in ethylene-propylene-diene rubber with 4.5 wt % of ethylidene norbornene diene content was increased progressively to 60 parts per hundred rubber by weight. The rubber compounds were cured via the tetrasulfane groups of the silane by adding sulfenamide accelerator and zinc oxide. The hardness, tensile strength, elongation at break, stored energy density at break, tear strength, Young’s modulus, M50-M300, compression set, cyclic fatigue life and bound rubber content of the rubber vulcanizates were measured. With the exception of the elongation at break and compression set which deteriorated, the remaining properties improved and the rate of cure, optimum cure time and crosslink density benefitted also when the loading of silica was increased in the rubber. The bound rubber content was unchanged and the cyclic fatigue life of the rubber vulcanizate enhanced considerably when silica was added. Optimizing the chemical bonding between the rubber and filler via the tetrasulfane groups of TESPT reduced the chemical curatives in the rubber. This was a major improvement in health, safety and environment.

Interfacial enhancement of fibrillar silicates (FSs)/EPDM nanocomposites by surface modification of FS in supercritical CO2

Abstract In this work, surface modification of fibrillar silicate (FS) is conducted by using supercritical CO2(sc-CO2) technique. For comparison purpose, conventional modification method is also carried out. The results showed that physical adsorption of the modifier (KH570) on FS surface dominated by using conventional method, whereas chemical adsorption dominated by using sc-CO2 technique. In addition, a more uniform adsorption of the modifier on FS surface is successfully obtained by using sc-CO2 method. This is ascribed to the special gaseous and liquid characteristics of sc-CO2, which can facilitate the diffuse and the full contact of KH570 on the whole surface of FS. The modified FS are then melt blended with ethylene–propylene ethylidene norbornene terpolymer (EPDM) to prepare rubber composites with excellent high temperature performance and good ageing resistance. The results showed that a more uniform dispersion of FS in EPDM matrix and a stronger interfacial interaction between FS and EPDM are successfully achieved by surface modification of FS in sc-CO2, which lead to the obviously enhanced mechanical properties of the composites. Our work demonstrates a better surface modification technique for FS to largely improve the interfacial interaction between FS and EPDM and to obtain a high performance FS/EPDM elastomer composites for its wide application such as transmission belts of automobile.

An autonomous self-healing system based on ROMP of norbornene dicarboximide monomers

This work reports the first example of an autonomous self-healing process at ambient temperature based on the ROMP of mono- and di-functional norbornene dicarboximides. The mixture of the mono- and di-functional norbornene dicarboximide monomers was successfully encapsulated by a method involving urea-formaldehyde and used as healing agents. All specimens were prepared by mixing microcapsules (10 wt%) Grubbs' ruthenium initiators RuCl2(=CHPh)(PCy3)2 (G1) (5 mol%) or RuCl2(=CHPh)(PCy3)(IMesH2) (G2) (2.5 mol%) with the epoxy resin components. Fracture tests were carried out at ambient temperature on all specimens using the compact tension geometry in order to determine a value for the critical stress intensity factor, KIC. The percentage of healing was calculated as the ratio of KIC after healing to that of the virgin test. It was found that while the specimens containing healing agent of high viscosity comprising of just a mixture of mono- and di-functional norbornene dicarboximide monomers required clamping to initiate healing, those containing healing agent of low viscosity comprising a mixture of these two monomers and 25 wt% of ethylidene norbornene, as a reactive diluent monomer, healed unclamped. The healing efficiency of 33% was observed and this developed between 11 and 24 h.

Micromechanical characterization of single-walled carbon nanotube reinforced ethylidene norbornene nanocomposites for self-healing applications

We report on the fabrication of self-healing nanocomposite materials, consisting of single-walled carbon nanotube (SWCNT) reinforced 5-ethylidene-2-norbornene (5E2N) healing agent—reacted with ruthenium Grubbs catalyst—by means of ultrasonication, followed by a three-roll mixing mill process. The kinetics of the 5E2N ring opening metathesis polymerization (ROMP) was studied as a function of the reaction temperature and the SWCNT loads. Our results demonstrated that the ROMP reaction was still effective in a large temperature domain ( − 15–45 °C), occurring at very short time scales (less than 1 min at 40 °C). On the other hand, the micro-indentation analysis performed on the SWCNT/5E2N nanocomposite material after its ROMP polymerization showed a clear increase in both the hardness and the Young modulus—up to nine times higher than that of the virgin polymer—when SWCNT loads range only from 0.1 to 2 wt%. The approach demonstrated here opens new prospects for using carbon nanotube and healing agent nanocomposite materials for self-repair functionality, especially in a space environment.

Studies on Pre-Ignition Reactions of Hydrocarbon-Based Rocket Fuels Hypergolic with Red Fuming Nitric Acid as Oxidizer

Carene, norbornadiene, ethylidene norbornene, and furfuryl alcohol exhibit hypergolic ignition with red fuming nitric acid as oxidizer. Carene, when blended with norbornadiene, ethylidene norbornene, and furfuryl alcohol in appropriate proportions, exhibits synergistic hypergolic ignition with further decrease in ignition delay. In order to understand the probable mechanism of hypergolic ignition and synergy in ignition, various pre-ignition reactions have been studied by quenching the reactions and analyzing the intermediate products by Fourier transform infrared (FTIR) and gas chromatography–mass spectrometry (GC-MS) techniques. Based on the product analysis, the probable schemes of reactions have been proposed. Oxidation, nitration, and cationic polymerization appear to be the important pre-ignition reactions taking place simultaneously that are responsible for hypergolic ignition.

Experimental and statistical study of the effects of material properties, curing agents, and process variables on the production of thermoplastic vulcanizates

AbstractA comprehensive experimental study together with statistical analysis was performed to identify the optimal process conditions, materials selection, and curing system for the production of thermoplastic vulcanizates (TPVs) based on EPDM rubber and polypropylene. Two types of curing systems were studied together with five different types of EPDM rubber. The TPV products were assessed according to elastic modulus and degree of swelling (indicators of crosslink density), ultimate tensile strength, ultimate elongation, tear strength, and compression set. A design of experiments method was applied to minimize the number of experiments and to obtain response surface and regression models for this complex and highly interactive system. From the modeling results, optimum values for the influential factors were obtained to achieve the target end product properties. It was found that a phenolic resin‐based curing system gave the best product properties and that the most influential factors were the rubber characteristics (ethylene content, ethylidene norbornene content, and molecular weight) and the polypropylene content in the formulation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

過酸化物架橋エチレンプロピレンゴムの残存過酸化物による劣化機構の解析

The chemical structures of aged dicumyl peroxide(DCP)-crosslinked EPDMs were investigated with FT-IR and 13C high-resolution solid state NMR. The mechanism of degradation induced by residual DCP was studied in DCP-crosslinked EPDMs.The thermal degradation of DCP-crosslinked EPDMs occurred with the disappearance of C=C bond of ethylidene norbornene and generation of carbonyl, carboxy and hydroxy groups and the scission of polymer chains. It can be considered that the residual DCP in DCP-crosslinked EPDMs accelerated the production of peroxide and hydroperoxide. The peroxide and hydroperoxide are extremely unstable, thereby causing various degradation reactions such as production of radicals, chain scission, and oxidation reactions of EPDM polymer.

Theoretical Evaluation and Experimental Validation of Performance Parameters of New Hypergolic Liquid Fuel Blends with Red Fuming Nitric Acid as Oxidizer

AbstractA number of fuel blends based on 3‐carene, norbornadiene, furfuryl alcohol, ethylidene norbornene, and kerosene in different weight proportions have been developed as rocket fuels which exhibit synergistic hypergolic ignition with red fuming nitric acid (RFNA) as oxidizer with low ignition delays (IDs<40 ms). The optimum compositions of fuel blends were determined by measuring ID values of different blends at optimum O/F ratios. Eight selected fuel blends and one neat fuel (ethylidene norbornene) were theoretically evaluated for their performance parameters using NASA‐CEC‐71 software with RFNA as oxidizer at different O/F ratios and at chamber pressure of Pc, 2451.66 and 4903.33 (or 5197.52) kPa, keeping the exit pressure constant at 98.07 kPa. For experimental validation of performance parameters, static firing trials of these fuel blends with RFNA were carried out using 735.5 N thruster at 2451.66 kPa chamber pressure using doublet or triplet impinging stream type of injector. The experimental C* values were compared with theoretically determined C* values to predict combustion efficiencies which were found to be more than 95% in all the cases.

Studies on ethylene‐propylene‐diene rubber modification by N‐chlorothio‐N‐butyl‐benzenesulfonamide

AbstractN‐Chlorothiosulfonamides have been used to modify ethylene‐propylene‐diene rubber (EPDM) to enhance the compatibility of EPDM in, e.g., natural rubber (NR)/butadiene rubber (BR)/EPDM blends for ozone resistance. N‐Chlorothio‐N‐butyl‐benzenesulfonamide (CTBBS) was selected as a representative for N‐chlorothiosulfonamides. In this study, we found that CTBBS behaves differently with various types of EPDM. Three types of EPDM were selected: ethylidene norbornene (ENB)‐EPDM, hexadiene (HD)‐EPDM, and dicyclopentadiene (DCPD)‐EPDM. HD‐EPDM showed the greatest effectiveness toward CTBBS‐modification. However, this EPDM is not commercially available anymore. On the opposite side, DCPD‐EPDM showed the lowest reactivity so that almost no modification could be realized. The result with ENB‐EPDM was, that upon application of CTBBS to ENB‐EPDM, gelation occurred and, therefore, a low amount of modification was achieved. With the limited modification efficiency for ENB‐EPDM, there is no significant improvement when applying the modified ENB‐EPDM into NR/BR/EPDM blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The influence of cross-linking agents on ring-opening metathesis polymerized thermosets

The addition of suitable cross-linking agents with norbornene-based monomers has significant effects on the thermal properties of the resulting polymers formed by olefin metathesis. Ethylidene norbornene (ENB) and endo-dicyclopentadiene (endo-DCPD) were mixed separately with various loadings of three different cross-linking agents and then polymerized with the addition of Grubbs’ catalyst. The polymerization kinetics and resulting glass transition temperature (T g) of the systems were evaluated by differential scanning calorimetry (DSC). The addition of the first cross-linking agent, norbornadiene (CL-1), to both endo-DCPD and ENB resulted in decreasing glass transition temperatures with increasing concentrations. In contrast, the addition of the other two cross-linking agents (CL-2 and CL-3), which were both custom synthesized bifunctional norbornyl systems, to both endo-DCPD and ENB resulted in a monotonic increases in T g with cross-linker concentration. By tailoring the loading of these custom cross-linking agents, the properties of these polymer systems can be controlled for various applications, including self-healing composites.

Antistatic coating and electromagnetic shielding properties of a hybrid material based on polyaniline/organoclay nanocomposite and EPDM rubber

Thermal, mechanical, electrical and microwave radiation absorbing properties of conductive composites based on dodecylbenzenesulfonate doped polyaniline/organoclay nanocomposites and propylene–ethylidene–norbornene rubber have been investigated with special interest on the effect of the nanocomposite concentration. Composites were prepared by melt blending using an internal mixer. Morphology studies by scanning electron microscopy of cryofractured surfaces indicated that the conducting nanocomposites produced heterogeneously distributed aggregates in the continuous elastomeric matrix. The composites exhibit high conductivities, up to 10 −3 S cm −1 for 40 wt.% of conducting nanocomposite, and good mechanical properties. They also present high microwave attenuation values, in the frequency range of 8–12 GHz. This property depends on the concentration of the conductive nanocomposite and on the film thickness. The composites can be used for antistatic coatings or for electromagnetic shielding.

Cure characterization and viscosity development of ring-opening metathesis polymerized resins

The ring-opening metathesis polymerization (ROMP) kinetics of three different norbornene-based monomers, ethylidene norbornene (ENB), endo-dicyclopentadiene (DCPD) and exo-DCPD, in the presence of Grubbs’ catalyst are examined using differential scanning calorimetry and rheokinetic viscosity measurements. Several different parameters were considered, such as, the monomer healing agents (including different monomer mixtures), the catalyst concentration, and test temperature to determine how these parameters influence cure development. The polymerization kinetics, quantified by exothermic peak locations in the case of differential scanning calorimetry and rheokinetic transition times in the case of viscosity measurements, are shown to be highly dependent on monomer type and catalyst concentration. The ENB monomer had the fastest kinetics even at the lowest catalyst concentration compared to the other diene monomers and mixtures.