scholarly journals Effect of the cure time on the Mechanical Properties of Silicone Rubber used as Socket Liners

2022 ◽  
Vol 961 (1) ◽  
pp. 012100
Author(s):  
Ahmed K Hassan ◽  
Zuhair Jabbar Abdul Ameer
Keyword(s):  
Silicone Rubber ◽  
Crosslink Density ◽  
Skin Inflammation ◽  
Moisture Stress ◽  
Curing Time ◽  
Cross Link ◽  
Local Pressure ◽  
Link Density ◽  
Cure Time ◽  
Cross Link Density

Abstract This work is focused on the upper part of the prosthesis which is called a socket, it is in contact connect with the amputated part. The shear force between skin and socket, local pressure, sweating, and bacteria generation, all lead to skin inflammation and a bad smell. Consequently, the prosthesis became uncomfortable for a patient. To address this issue silicone rubber liners is proposed to use because it can absorb moisture, stress distribution, and anti-bacterial. The curing time and temperature are important factors for determining crosslink density, from the results obtained, can be noticed that, the cross-link density can greatly affect the silicone rubber properties, it can have a direct effect on the tensile strength, modulus of elasticity, percentage of elongation as well as the water absorption, and the cure time (15 min.) shoes the best resalt. As a result, using it making the prosthesis more comfortable and acceptable to the patient. In this paper, the effect of cure time on physical properties was studied.

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%.

Elongation at Break as a Measure of Cross-Link Density in Vulcanized Elastomers

1966 ◽  
Vol 39 (3) ◽  
pp. 726-739 ◽  
Author(s):  
E. DiGiulio ◽  
G. Bellini ◽  
G. V. Giandinoto
Keyword(s):  
Crosslink Density ◽  
Cross Linking ◽  
Total Degree ◽  
Cross Link ◽  
Elongation Ratio ◽  
Elongation At Break ◽  
Ethylene Propylene ◽  
First Approximation ◽  
Link Density ◽  
Cross Link Density

Abstract After recalling the reaction mechanism suggested for the crosslinking of ethylene propylene copolymers with organic peroxides, the authors consider the relation between concentration of curing agent and crosslink density. It is experimentally found that, as a first approximation, the elongation ratio at break of vulcanizates (unfilled or filled with small quantities of carbon black) is a function of molar concentration of peroxide only: αR=K/P1/2 This relation can be theoretically justified on the basis of the extensibility of polymer chain segments and of the criterion for rupture originally put forward by Taylor and Darin. By applying the above relation to ethylene propylene copolymers it is possible to evaluate the influence of the chain-splitting reaction during cross-linking. The reciprocal of the square of elongation ratio at break (1/αR2) measures the total degree of crosslinking.

scholarly journals Influence of trans-polyoctylene rubber content on styrene-butadiene rubber properties

2020 ◽  
Vol 13 (1) ◽  
pp. 1-5
Author(s):  
Patrik Macúrik ◽  
Rafal Anyszka ◽  
Ivan Hudec ◽  
Terézia Malčeková ◽  
Ján Kruželák
Keyword(s):  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Curing Time ◽  
Cross Link ◽  
Rubber Content ◽  
Elongation At Break ◽  
Rubber Compounds ◽  
Link Density ◽  
Cross Link Density ◽  
Styrene Butadiene

AbstractThe study was focused on the investigation of trans-polyoctylene (TOR) influence on cross-linking as well as mechanical and rheological properties of rubber compounds based on styrene-butadiene rubber (SBR). SBR was compounded with different proportions of TOR in the concentration range from 0 to 30 phr. Integration of TOR into rubber leads to the prolongation of the optimum curing time and scorch time and thus the decrease of the curing rate. Higher content of TOR led to less viscous rubber due to the plasticizing effect. Cross-link density of vulcanizates was reduced, which correlates with higher elongation at break. Tensile strength and hardness of vulcanizates increased with the increasing TOR content, probably due to the increasing amount of the crystalline phase.

VULCANIZATION CHARACTERISTICS OF NATURAL RUBBER COAGULATED BY MICROORGANISMS

2018 ◽  
Vol 91 (1) ◽  
pp. 64-78
Author(s):  
Si-Dong Li ◽  
Jing Chen ◽  
Le-Fan Li ◽  
Zhi-Fen Wang ◽  
Jie-Ping Zhong ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Natural Rubber ◽  
Transverse Relaxation Time ◽  
Cross Link ◽  
Mass Percentage ◽  
Transverse Relaxation ◽  
1H Nuclear Magnetic Resonance ◽  
Link Density ◽  
Cure Time ◽  
Cross Link Density

ABSTRACT The network variations of natural rubber (NR) during the vulcanization process were investigated by 1H chemical shift by liquid-state 1H nuclear magnetic resonance (NMR) spectroscopy. NR latex coagulated by microorganisms (NR-m) was contrasted with NR latex coagulated by acid (NR-a). The influences of the coagulation process on the structures, vulcanization characteristics, and mechanical properties of NR were analyzed. The results show that the cross-link density (XLD) and mass percentage of cross-link network (A(Mc)) can be increased with the increment of the vulcanization time; while the mass percentage of dangling free ends of the hydrocarbon and small molecules (A(T2)), the longitudinal relaxation time (T1), transverse relaxation time (T2), and molecular mass of inter–cross-link chains (Mc) decreased with the prolonging of vulcanization time both NR-m and NR-a. NR-m exhibits shorter scorch times (ts1, ts2) and optimum cure time (t90) and shows higher maximum torque (MH) and minimum torque (ML) than that of NR-a. It is obvious that the higher XLD and A(Mc) and lower A(T2), T1, T2, and Mc values of NR-m result in higher stress, tensile strength, and tear strength of NR compounds.

scholarly journals Preparation and Charaterization of Treated BIS [3-(Triethoxysilyl) Propyl] Tetrasulfide (Si-69) -HYBRID CB/PCC Fillers Reinforced NR/SBR Composites: Cure Characteristic, Mooney Viscosity and Cross-Link Density

2018 ◽  
Vol 27 (6) ◽  
pp. 096369351802700
Author(s):  
Siti Nur Liyana Mamauod ◽  
Basirah Fauzi ◽  
Nor Atiqah Suhaimi ◽  
Roslinda Fauzi ◽  
Ahmad Zafir Romli
Keyword(s):  
Crosslink Density ◽  
Network Formation ◽  
Cross Link ◽  
Hybrid Filler ◽  
Curing Characteristics ◽  
Roll Mill ◽  
Link Density ◽  
Cross Link Density ◽  
Mooney Viscosity ◽  
Cure Characteristic

Hybridization of silanized CB/PCC filler reinforced NR/SBR blends was prepared on a two roll mill. The si-CB/PCC composites were vulcanized via a conventional sulphur system at 180°C. The primary aims of this research are to scrutinize the effects of different concentration of si treated hybrid CB/PCC fillers ranging from 2 wt. % to 10 wt. % on the NR/SBR blends properties towards the curing characteristics, viscosity and crosslink density. In this work, a positive correlation was found between silane content on the hybrid filler surface and NR/SBR blend properties. It was found that at 6% of Si 69 concentration (F4) provided improvement in crosslink density and mooney viscosity properties. Increment of crosslink density in the blends would increase the viscosity and it may be due to the network formation between the treated fillers and rubber molecules. Moreover, the incorporation of treated fillers accelerates the curing process due to the surface activation and hence leads to tightly contact between filler-rubber phases.

scholarly journals Multivalency in healable supramolecular polymers: the effect of supramolecular cross-link density on the mechanical properties and healing of non-covalent polymer networks

2014 ◽  
Vol 5 (11) ◽  
pp. 3680-3688 ◽  
Author(s):  
Lewis R. Hart ◽  
James H. Hunter ◽  
Ngoc A. Nguyen ◽  
Josephine L. Harries ◽  
Barnaby W. Greenland ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymer Blends ◽  
Crosslink Density ◽  
Polymer Networks ◽  
Supramolecular Polymers ◽  
Supramolecular Polymer ◽  
Cross Link ◽  
Link Density ◽  
Cross Link Density

Mechanical properties of healable supramolecular polymer blends correlate to non-covalent “crosslink density”.

INVESTIGATION OF THE VULCANIZATION CHARACTERISTICS OF NATURAL RUBBER COAGULATED BY MICROORGANISMS

2017 ◽  
Vol 90 (3) ◽  
pp. 521-535 ◽  
Author(s):  
Si-Dong Li ◽  
Jing Chen ◽  
Le-Fan Li ◽  
Zhi-Fen Wang ◽  
Jie-Ping Zhong ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Transverse Relaxation Time ◽  
Cross Link ◽  
Mass Percentage ◽  
Maximum Torque ◽  
Transverse Relaxation ◽  
Link Density ◽  
Cure Time ◽  
Cross Link Density ◽  
Vulcanization Process

ABSTRACT The network variations of NR during the vulcanization process were investigated by 1H chemical shift by liquid-state 1H-NMR spectroscopy. NR latexes coagulated by microorganisms (NR-m) or acid (NR-a) were contrasted. The influences of coagulation on the structures, vulcanization characteristics, and mechanical properties of NR were analyzed. The results show that the cross-link density (XLD) and mass percentage of cross-link network [A(Mc)] increased with the increment of the vulcanization time, whereas the mass percentage of bangling free ends of the hydrocarbon and small molecules [A(T2)], the longitudinal relaxation time (T1), the transverse relaxation time (T2), and the molecular mass of inter–cross-link chains (Mc) decreased with the prolonging of vulcanization time for both NR-m and NR-a. Although NR-m exhibits shorter scorch times and optimum cure time, it shows higher maximum torque and minimum torque than that of NR-a. It is obvious that the higher XLD and A(Mc), the lower the A(T2), T1, T2, and Mc values of NR-m, resulting in higher stress, tensile strength, and tear strength of NR compounds.

Mechanical and structural consequences of associative dynamic cross-linking in acrylic diblock copolymers

2021 ◽  
Author(s):  
Jacob Ishibashi ◽  
Ian Pierce ◽  
Alice Chang ◽  
Aristotelis Zografos ◽  
Bassil El-Zaatari ◽  
...  
Keyword(s):  
Viscoelastic Properties ◽  
Diblock Copolymers ◽  
Microphase Separation ◽  
Network Connectivity ◽  
Ethyl Acrylate ◽  
Cross Linking ◽  
Cross Link ◽  
Block Polymers ◽  
Link Density ◽  
Cross Link Density

<p>The composition of low-T<sub>g</sub> <i>n</i>-butylacrylate-<i>block</i>-(acetoxyaceto)ethyl acrylate block polymers is investigated as a strategy to tune the properties of dynamically cross-linked vinylogous urethane vitrimers. As the proportion of the cross-linkable block is increased, the thermorheological properties, structure, and stress relaxation evolve in ways that cannot be explained by increasing cross-link density alone. Evidence is presented that network connectivity defects such as loops and dangling ends are increased by microphase separation. The thermomechanical and viscoelastic properties of block copolymer-derived vitrimers arise from the subtle interplay of microphase separation and network defects.</p><div><br></div><p></p>

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