The effect of lanthanum trimethacrylate on the mechanical properties and flame retardancy of dynamically vulcanized PP/EPDM thermoplastic vulcanizates

2017 ◽  
Vol 50 (4) ◽  
pp. 339-353 ◽  
Author(s):  
Quan Zhou ◽  
Lu Yan ◽  
Xuejun Lai ◽  
Hongqiang Li ◽  
Xingrong Zeng
Keyword(s):  
Mechanical Properties ◽  
Flame Retardancy ◽  
Thermoplastic Elastomer ◽  
Cross Link ◽  
Dynamic Vulcanization ◽  
Sem Images ◽  
Limiting Oxygen Index ◽  
Reinforcing Agent ◽  
Link Density ◽  
Cross Link Density

A new kind of polypropylene/ethylene–propylene–diene monomer (PP/EPDM) thermoplastic elastomer (TPE) with good mechanical properties and flame retardancy was prepared via in situ peroxide-induced dynamic vulcanization using lanthanum trimethacrylate (LaTMA) as a reinforcing agent. The morphology, structure, and mechanical properties and reinforcement mechanism of PP/EPDM/LaTMA TPE were investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, rubber process analyzer, cross-link density test, and so on. The flame retardancy was investigated by limiting oxygen index (LOI) test. The results showed that when the amount of lanthanum oxide was 4.96 phr and methyl methacrylate was 7.85 phr, the compatibility between EPDM and PP was greatly improved. Besides, the tensile strength, tear strength, elongation at break, and hardness (shore A) of PP/EPDM/LaTMA TPE were increased from 6.2 MPa, 41.7 kN m−1, 148%, and 81 up to 11.1 MPa, 77.3 kN m−1, 365%, and 89, respectively. And the LOI of PP/EPDM/LaTMA TPE was increased to 19.0%. The SEM images, the higher G′, and the ionic cross-link suggested that a strong filler–filler network was formed by the polymerization and the grafted of LaTMA in the PP and EPDM phase which enhanced the compatibility between PP and EPDM. The DSC and FTIR results further proved that during the processing.

Boron nitride for modification of rubber based on isoprene elastomer

2020 ◽  
pp. 105-112
Author(s):  
K. S. Zhansakova ◽  
E. N. Eremin ◽  
G. S. Russkikh ◽  
O. V. Kropotin
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Gradual Increase ◽  
Physical And Mechanical Properties ◽  
Curing Time ◽  
Cross Link ◽  
Start Time ◽  
Link Density ◽  
Cross Link Density ◽  
Isoprene Rubber

The work studies vulcanization characteristics of elastomers based on isoprene rubber filled with carbon black N330 and boron nitride (BN). The influence of the boron nitride (BN) concentration on technological, dynamic, physical and mechanical properties of elastomers has been researched. The application of boron nitride for producing rubber with good properties has been considered. With a gradual increase of the inert filler BN concentration up to 35%, a decrease in the curing rate by 33% and polymer cross-link density by 26% is observed. Moreover, the start time of vulcanization increases by almost 300%, the optimal curing time by 200%.

PEG Cross-Linked Alginate Hydrogels with Controlled Mechanical Properties

1998 ◽  
Vol 530 ◽  
Author(s):  
Petra Eiselt ◽  
Jon A. Rowley ◽  
David J. Mooney
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Molecular Weight ◽  
Elastic Modulus ◽  
Cell Transplantation ◽  
Cross Linking ◽  
Cross Link ◽  
Link Density ◽  
A Cell ◽  
Cross Link Density

AbstractReconstruction of tissues and organs utilizing cell transplantation offers an attractive approach for the treatment of patients suffering from organ failure or loss. Highly porous synthetic materials are often used to mimic the function of the extracellular matrix (ECM) in tissue engineering, and serve as a cell delivery vehicle for the formation of tissues in vivo. Alginate, a linear copolysaccharide composed of D-mannuronic acid (M) and L-guluronic acid (G) units is widely used as a cell transplantation matrix. Alginate is considered to be biocompatible, and hydrogels are formed in the presence of divalent cations such as Ca2+, Ba2+ and Sr2+. However, ionically cross-linked alginate gels continuously lose their mechanical properties over time with uncontrollable degradation behavior. We have modified alginate via covalent coupling of cross-linking molecules to expand and stabilize the mechanical property ranges of these gels. Several diamino PEG molecules of varying molecular weight (200, 400, 1000, 3400) were synthesized utilizing carbodiimide chemistry. Sodium alginate was covalently cross-linked with these cross-linking molecules, and mechanical properties of the resulting hydrogels were determined. The elastic modulus of the cross-linked alginates depended on the molecular weight of the cross-linking molecules, and ranged from 10-110 kPa. The theoretical cross-link density in the hydrogels was also varied from 3 to 47% (relative to the carboxylic groups in the alginate) and the mechanical properties were measured. The elastic modulus increased gradually and reached a maximum at a cross-link density of 15%. In summary, covalently coupled hydrogels can be synthesized which exhibit a wide range of mechanical properties, and these materials may be useful in a number of tissue engineering applications.

scholarly journals Application of Peroxide Curing Systems in Cross-Linking of Rubber Magnets Based on NBR and Barium Ferrite

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Ján Kruželák ◽  
Andrea Kvasničáková ◽  
Elena Medlenová ◽  
Rastislav Dosoudil ◽  
Ivan Hudec
Keyword(s):  
Mechanical Properties ◽  
Barium Ferrite ◽  
Cross Linking ◽  
Butadiene Rubber ◽  
Cross Link ◽  
System Composition ◽  
Peroxide Curing ◽  
Link Density ◽  
Cross Link Density ◽  
Curing Systems

Rubber magnetic composites were prepared by incorporation of barium ferrite in constant amount—50 phr into acrylonitrile-butadiene rubber. Dicumyl peroxide as the curing agent was used for cross-linking of rubber magnets alone, or in combination with four different types of co-agents. The main aim was to examine the influence of curing system composition on magnetic and physical-mechanical properties of composites. The cross-link density and the structure of the formed cross-links were investigated too. The results demonstrated that the type and amount of the co-agent had significant influence on cross-link density, which was reflected in typical change of physical-mechanical properties. The tensile strength increased with increasing amount of co-agents, which can be attributed to the improvement of adhesion and compatibility on the interphase filler-rubber due to the presence of co-agents. Magnetic characteristics were found not to be influenced by the curing system composition. The application of peroxide curing systems consisting of organic peroxide and co-agents leads to the preparation of rubber magnets with not only good magnetic properties but also with improved physical-mechanical properties, which could broaden the sphere of their application uses.

scholarly journals Novel Intumescent Flame Retardant Masterbatch Prepared Through Different Processes and Its Application in EPDM/PP Thermoplastic Elastomer: Thermal Stability, Flame Retardancy, and Mechanical Properties

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 50 ◽  
Author(s):  
Weidi He ◽  
Ying Zhou ◽  
Xiaolang Chen ◽  
Jianbing Guo ◽  
Dengfeng Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Flame Retardancy ◽  
Flame Retardants ◽  
Thermoplastic Elastomer ◽  
Molar Ratio ◽  
Limiting Oxygen Index ◽  
Cone Calorimeter Test ◽  
Properties Of Materials ◽  
Intumescent Flame Retardants

In this work, the ethylene-propylene-diene monomer/polypropylene (EPDM/PP) thermoplastic elastomer filled with intumescent flame retardants (IFR) is fabricated by melting blend. The IFR are constituted with melamine phosphate-pentaerythritol (MP/PER) by compounding and reactive extruding, respectively. The effects of two kinds of MP/PER with different contents on the thermal stability, flame retardancy, and mechanical properties of materials are investigated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL-94, cone calorimeter test (CCT), and scanning electron microscopy (SEM). FTIR results show that the reactive extruded MP/PER partly generates melamine pyrophosphate (MPP) compared with compound masterbatches. TGA data indicate that the best thermal stability is achieved when the molar ratio of MP/PER reaches 1.8. All the reactive samples show a higher flame retardancy than compound ones. The CCT results also exhibit the same trend as above in heat release and smoke production rate. The EPDM/PP composites filled with 30 and 35% reactive MP/PER exhibit the improved flame retardancy but become stiffer and more brittle. SEM photos display that better dispersion and smaller particle size are obtained for reactive samples.

RECLAIMING OF GROUND RUBBER TIRE BY SAFE MULTIFUNCTIONAL RUBBER ADDITIVES: I. TETRA BENZYL THIURAM DISULFIDE

2012 ◽  
Vol 85 (4) ◽  
pp. 629-644 ◽  
Author(s):  
Swapan Kumar Mandal ◽  
Najib Alam ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Milling Time ◽  
Mechanical Performance ◽  
Cross Link ◽  
Time Intervals ◽  
Gel Content ◽  
Rubber Tire ◽  
Ground Rubber ◽  
Link Density ◽  
Cross Link Density

ABSTRACT The present paper describes the mechanical reclaiming of ground rubber tire (GRT) by safe tetra benzyl thiuram disulfide (TBzTD), a multifunctional rubber additive. The versatility of the proposed agent is that it acts as a reclaiming agent during reclaiming and as a curing agent during revulcanization of the reclaimed materials. In this regard, we want to introduce a safe reclaiming agent in reclamation of GRT for improving its physical and mechanical performance. Reclaiming GRT has been carried out in an open roll mixing mill at various time intervals and different concentrations of the reclaiming agent (TBzTD) in the presence of spindle oil. The degree of reclaiming has been evaluated by the measurement of sol content, gel content, Mooney viscosity, inherent viscosity of sol rubber, and degree of cross-link of the reclaimed materials as a function of milling time. Also, the influence of gel content on cross-link density at various time intervals on the open two roll mixing mill has been determined. A unique correlation between gel fraction and cross-link density obtained at various time intervals and concentrations of reclaiming agent indicate that an optimization of the concentration of safe TBzTD and milling time has a positive influence on improving the efficiency of reclamation. The reclaiming conditions have been optimized in view of the mechanical properties of the revulcanized GRT and the aging resistance properties of the revulcanized reclaim. The influences of the concentration on the mechanical properties in the revulcanized reclaim have also been studied. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the revulcanized reclaimed rubber when reclamation is carried out by optimum concentration of safe TBzTD after maximum time of reclaiming.

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