Predicting optimum cure time of rubber compounds by means of ANFIS

2012 ◽  
Vol 35 ◽  
pp. 833-838 ◽  
Author(s):  
Bağdagül Karaağaç ◽  
Melih İnal ◽  
Veli Deniz
Keyword(s):  
Rubber Compounds ◽  
Cure Time

Calophyllum Inophyllum Oil as Plasticizer in Natural Rubber Compounds

2009 ◽  
Vol 25 (2) ◽  
pp. 113-128 ◽  
Author(s):  
P. Raju ◽  
V. Nandanan ◽  
Sunil K.N. Kutty
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Thermal Studies ◽  
Calophyllum Inophyllum ◽  
Compression Set ◽  
Peak Rate ◽  
Rubber Compounds ◽  
Cure Time ◽  
Calophyllum Inophyllum Oil ◽  
Control Compound

Mechanical properties and the thermal degradation characteristics of natural rubber compounds with calophyllum inophyllum oil were compared to that of the control compound containing naphthenic oil. The compounds containing calophyllum inophyllum oil showed improved tensile strength, tear strength, modulus, compression set, abrasion resistance and resilience. Cure time was higher than the naphthenic oil mixes. Thermal studies showed an increase of 8 °C in the temperature of initiation of degradation and an increase of 6 °C in temperature at which the peak rate of degradation occurred. The peak rate of degradation was comparable to the control mix containing naphthenic oil.

The Effect of Excess Silane-69 Used for Surface Modification on Cure Characteristic and Mechanical Properties of Precipitated Silica Filled Natural Rubber (PSi/NR)

2009 ◽  
Vol 79-82 ◽  
pp. 2171-2174 ◽  
Author(s):  
Chanchai Thongpin ◽  
C. Sangnil ◽  
P. Suerkong ◽  
A. Pongpilaiprertti ◽  
Narongrit Sombatsompop
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Crosslinking Density ◽  
High Concentration ◽  
Precipitated Silica ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Cure Time ◽  
Cure Characteristic ◽  
Characterization Test

This research is concentrated on the effect of concentration of silane-69 used for surface modification on precipitated silica (PSi), on cure characteristic and mechanical properties of PSi filled NR. The PSi content in this study was fixed at 20 phr in order to reveal the effect of silane used to modify PSi, on NR compound and vulcanizate. Moving Die Rheometer (MDR) was used to characterize cure characteristic of rubber compounds. Generally, scorch and cure time of NR would increase with the addition of PSi due to the absorption of accelerator on its surface whereas the addition of Si-69 modified PSi would reduce both scorch and cure time. It was found in this research that the excess amount of Si-69 used increased scorch and cure time of rubber compounds. This was thought to be that the excess of Si-69 led to the formation of polysiloxane clusters which could absorb accelerator in rubber compound and resulted in a prolonged scorch and cure time. In term of vulcanized rubber, it was found that maximum torque increased with the concentration of Si-69 up to 6 %. The polysiloxane formed during the cure characterization test was responsible for the slightly decreased torque after 6% of Si-69 treatment. Nonetheless, even with high concentration of Si-69 used, torque was still higher than that of untreated PSi filled NR. This is widely understood that sulfur atoms in Si-69 molecule are able to participate in the bonding between rubber and silane molecules resulted in the enhancement of crosslink density of the vulcanizate rubber. The increased of modulus at 200 % elongation, tensile strength under tension, with the silane concentration, was evidence of the crosslink enhancement. Tear strength and hardness of the vulcanizates exhibiting the increment, with the silane used, also clearly confirmed the bonding between Si-69 and rubber molecules. It was elucidated from the research that excess of Si-69 would lead to polysiloxane formation, cluster form of silane and crosslinking density. Scanning Electron Microscope (SEM) micrographs and swelling test are also presented to confirm the phenomena.

The Effect of Second Filler on Cure Characteristic and Mechanical Properties of Si-69 Treated Precipitate Silica/NR Composite

2009 ◽  
Vol 79-82 ◽  
pp. 2183-2186 ◽  
Author(s):  
Chanchai Thongpin ◽  
C. Sripetdee ◽  
N. Papaka ◽  
N. Pongsathornviwa ◽  
Narongrit Sombatsompop
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Rubber Compound ◽  
Maximum Torque ◽  
Elongation At Break ◽  
Rubber Vulcanizate ◽  
Rubber Compounds ◽  
Cure Time ◽  
Cure Characteristic

Silica has been widely used as non-black reinforcing filler, however, the filler-filler interaction has been an important issue. Cure characteristic and mechanical properties of the rubber compound and rubber vulcanizate were affected both by filler-rubber interaction and filler-filler interaction. There have been, presently, a number of natural fillers which are also used as fillers for the rubber, i.e. fly ash, sawdust and zeolite. This work therefore will study the effect of second filler added into the 13% Si-69 treated precipitate silica (PSi) filled natural rubber compounds. It was revealed that the scorch and cure time of the rubber compound increased with the content of treated PSi. This was the effect of excess of the silane treated onto PSi which would agglomerate and form the cluster of polysiloxane and would then be able to absorb vulcanizing accelerator resulting in extending the scorch and cure time of the rubber compounds. However, this effect was over ruled with the reinforcing effect as could be seen by the increasing, with the contents of PSi, of maximum torque and mechanical properties of the vulcanizates. The NR compounded with treated PSi content of 20 phr selected to study the effect of excess silane on the cure characteristic of hybrid fillers NR composite. The addition of sawdust led to longer scorch time and cure time but not much change of the maximum torque. As expected, the modulus of the rubber vulcanizate increased with the sawdust content whereas the tensile strength and elongation at break decreased with the sawdust content. The incorporation of zeolite could accelerate the cure reaction therefore both scorch time and cure time decreased. The maximum torque also increased with the content of zeolite. Both modulus and tensile strength increased with the content of the zeolite whereas elongation at break tended to be unchanged. In the case of using fly ash as the second filler, the cure time tended to be unchanged. However, the maximum torque tended to be increased with the content of fly ash. It was found that the modulus, tensile strength increased but elongation at break decreased. Interestingly, the excess of Si-69 used effect pronouncedly for the addition of zeolite and fly ash cases as the excess silane could promote the interaction between fillers surface and rubber molecule accept for sawdust

Preliminary Study on Curing of Thick Rubber Article

2015 ◽  
Vol 1134 ◽  
pp. 23-27
Author(s):  
Siti Zulaikha Ibrahim ◽  
Che Mohd Som Said ◽  
Mohamad Asri Ahmad ◽  
Azemi Samsuri
Keyword(s):  
Tensile Strength ◽  
Temperature Region ◽  
The State ◽  
Curing Temperature ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Cure Time ◽  
Zinc Diethyldithiocarbamate ◽  
Preliminary Study ◽  
Rubber Article

In this study, several batches of natural rubber (SMR L) were compounded with three different types of accelerators, which were N-cyclohexylbenzothiazole-2-sulphenamide (CBS), diphenylguanidine (DPG) and zinc diethyldithiocarbamate (ZDEC). ZDEC is known as an ultrafast accelerator. The rubber compounds were cured at 140°C, 130°C, 120°C, 110°C and 100°C in accordance with the temperature gradients observed within the thick rubber block. The main aim of this study is to cure the rubber at each temperature region to the same cure time as that of the outermost region (20 minutes at 140°C). The amount of sulfur and accelerator were adjusted accordingly at each curing temperature to match the state of cure at 140°C. The state of cure of of the vulcanized rubbers were measured using hardness and tensile strength. The same state of cure is achieved if the hardness and tensile strength value are within ±2 IRHD and ±3 MPa, respectively with that of the control vulcanized rubber (hardness and tensile strength cured at 140°C). The results shows that the hardness and tensile strength of the vulcanized rubber at each temperature region are within the expected margins. The results clearly indicated that the type and amount of accelerators, and the amount of sulfur were correctly chosen at each temperature.

Photocatalytic Activity and Properties of Nanotitanium Dioxide-Filled Natural Rubber in the Presence of Coupling Agents

2015 ◽  
Vol 659 ◽  
pp. 474-478
Author(s):  
Pornsiri Toh-Ae ◽  
Banja Junhasavasdikul ◽  
Natinee Lopattananon ◽  
Kannika Sahakaro
Keyword(s):  
Photocatalytic Activity ◽  
Natural Rubber ◽  
Coupling Agent ◽  
Inorganic Filler ◽  
White Pigment ◽  
Photodegradation Efficiency ◽  
Rubber Compounds ◽  
Cure Time ◽  
The Difference ◽  
Direct Incorporation

Titanium dioxide (TiO2) is normally added into the rubber compounds as a white pigment and inorganic filler for an improvement of thermal property. TiO2 is also known to have an outstanding photocatalytic activity. This work investigates the properties of natural rubber (NR) compounds filled with 5 phr of nanoTiO2 (n-TiO2). Since the direct incorporation of n-TiO2 into NR encounters incompatibility problem, therefore two types of coupling agent (i.e. bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) and isopropyl trioleyl titanate (ITT)) are used. The coupling agent loading is varied in a range of 0-20 wt% relative to the n-TiO2. Mooney viscosities and minimum cure torque (ML) of the compounds increase with increasing coupling agent content and the ones with ITT show higher viscosity than the mixes with TESPT. The use of TESPT leads to shorter optimum cure time and higher torque difference compared to the use of ITT. The addition of n-TiO2 results in the improved modulus, reinforcing index and tensile strength compared to the unfilled vulcanizate. The presence of both TESPT and ITT significantly reduces a photodegradation efficiency. The difference in the properties and photocatalytic activity of n-TiO2 filled NR having TESPT and ITT as coupling agent indicates their possible different level of dispersion and interactions at the interphases.

Cure Characteristic and Mechanical Properties of Epoxidized Natural Rubber/Chloroprene (ENR/CR) Blends

2010 ◽  
Vol 93-94 ◽  
pp. 631-634
Author(s):  
Chanchai Thongpin ◽  
Piyaporn Niltui ◽  
Piyapong Sornwaneenawakhun ◽  
Tossaporn Maneeprom ◽  
Saovaros Malithong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Maximum Torque ◽  
Tear Strength ◽  
Rubber Compounds ◽  
Cure Time ◽  
Chloroprene Rubber ◽  
Cure Characteristic ◽  
Two Phases

Epoxidized Natural rubber (ENR) with the epoxide content of 40 % was prepared and blended with various contents of chloroprene rubber (CR) and 50 phr of carbon black. The cure characteristic, mechanical properties and the effect of gasohol E-85 on the mechanical properties of the rubber vulcanizate were studied. It was revealed from cure characteristic results, tested by Moving Die Rheometer (MDR), that minimum torque of the rubber compounds increased with the content of CR whereas maximum torque tended to increase at the content of 10 phr and decrease after this content, of which the values agreed well with the modulus at 100% elongation in rubber vulcanizates. Considering characteristic scorch and cure time, the values increased with the CR contents. It was clear from the result that at the ENR:CR ratio of 90:10, modulus of 100% elongation and tear strength exhibited the highest values. It was also found that the mechanical properties of the blend vulcanizates were slightly suffered by gasohol E85 except for tear strength. It was understood that this must be because of the effect of the phase continuity and crosslinking that occurred differently in two phases. The phase morphology of the blends were also investigated and reported in the research.

The Effects of Various Ratios of Hybrid Filler to Rubber Vulcanisates Properties Based on Passenger Car Tyre Tread Compounds

2020 ◽  
Vol 856 ◽  
pp. 169-174
Author(s):  
Chatchatree Thongsaen ◽  
Pongdhorn Sea-Oui ◽  
Chakrit Sirisinha
Keyword(s):  
Rolling Resistance ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Hybrid Filler ◽  
Rubber Compounds ◽  
Hybrid Fillers ◽  
Cure Time ◽  
Filler Dispersion ◽  
Styrene Butadiene ◽  
Good Agreement

Solution styrene-butadiene rubber (SSBR) reinforced by hybrid fillers of carbon black (CB) and silica (PSi) was prepared with various CB/PSi ratios. Rheological and mechanical properties of rubber compounds and vulcanisates were investigated. Results of compounds demonstrate that, with increasing CB fraction, increases in the magnitude of the Payne effect and Mooney viscosity were found. On the contrary, with increased loading of PSi, increases in optimum cure time (tc90) and cure torque difference were evidenced. The results suggest superiority in filler dispersion level and cure efficiency in the systems filled with high PSi fraction due to the presence of Bis [3-(triethoxysilyl) propyl] tetrasulphide (TESPT or Si-69) as a silane coupling agent. As for vulcanisate properties, the systems with increased PSi fraction exhibit enhancement in mechanical strength and elastic contribution, which are in good agreement with rubber compound properties. Also, the decrease in loss factor at 60 °C was observed with increasing PSi fraction, suggesting the desirable reduction in rolling resistance of tyre tread.

The Effects on the Cure Characteristics and Physical Properties of Bamboo Activated Carbon Filled Styrene Butadiene Rubber (SBR) Compounds

2015 ◽  
Vol 815 ◽  
pp. 24-28
Author(s):  
N.R. Munirah ◽  
N.Z. Noriman ◽  
M.Z. Salihin ◽  
H. Kamarudin ◽  
M.H. Fatin ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Physical Properties ◽  
Filler Loading ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Cure Characteristics ◽  
Rubber Compounds ◽  
Roll Mill ◽  
Cure Time ◽  
Styrene Butadiene

The role of activated carbon (AC) in rubber compounds was investigated to better understand the reinforcing mechanism. The activated carbon filled styrene butadiene rubber vulcanizates (SBR-AC) using bamboo activated carbon as filler were prepared by using two-roll mill and cured at 160 °C. AC filler loading from 10 to 50 phr (part per hundred rubber) were used in this study. Study into the influences of filler loading on the cure characteristics, swelling behaviour and physical properties (hardness and resilience) of SBR-AC vulcanizates were carried out. It was observed that SBR-AC vulcanizates has better cure characteristics compared to the styrene butadiene rubber gum vulcanizate (SBR-GV) which is a non-filled vulcanizate. The results showed that the scorch time (ts2) decreased with increasing filler loading. The cure time (tc90) slightly decreased up to 20 phr before a rise as the filler loading increased. The minimum torque (ML) of SBR vulcanizate increased and the maximum torque (MH) decreased up to 20 phr but then increased with increasing filler loading. The cure rate index (CRI) of SBR-GV vulcanizate was higher than that of all SBR-AC vulcanizates. Up to 20 phr of filler loading, the CRI increased before a decline occurred as the filler loading increased. As expected, the hardness value of SBR-AC vulcanizates was higher compared to SBR-GV vulcanizate which has lower resilience. The hardness and crosslink density showed an increasing trend meanwhile the resilience was adversely affected by the increase in filler loading. Bamboo activated carbon showed some potential enhancement on the reinforcing and physical properties of the vulcanizates.

CALCULATION OF TIMES AND TEMPERATURES FOR PRESS VULCANIZATION OF THICK RUBBER PADS

2017 ◽  
Vol 90 (1) ◽  
pp. 89-107 ◽  
Author(s):  
Julia Gough
Keyword(s):  
Element Analysis ◽  
Thin Sections ◽  
Press Temperature ◽  
Rubber Compounds ◽  
Python Scripting ◽  
Cure Time ◽  
Flow Through ◽  
Fast Cooling ◽  
Cure Temperature ◽  
Simple Equations

ABSTRACT Rubber manufacturers need simple rules to enable them to find the correct cure time and temperature for thick articles. To this end finite element analysis, controlled by Python scripting, has been used to calculate press times that meet specifications for adequate cure for uniaxial heat flow through molded rubber pads over a range of thicknesses. Three press temperatures, the effect of first preheating the rubber, and the rate of cooling were investigated. A low press temperature, preheating of the rubber, and fast cooling were required to achieve a reasonably even state of cure through thick moldings. The heat of vulcanization was included in some of the models. Its effect was small. Unified plots of the simulation results for five commercial rubber compounds are presented, and simple equations are provided to enable the cure time at any cure temperature to be estimated. The applicability of the results to fast cures of thin sections is discussed.

Mechanistic Investigations into the Adhesion between RFL-Treated Cords and Rubber. Part I: The Influence of Rubber Curatives

2007 ◽  
Vol 80 (4) ◽  
pp. 545-564 ◽  
Author(s):  
W. B. Wennekes ◽  
J. W. M. Noordermeer ◽  
R. N. Datta
Keyword(s):  
Adhesion Force ◽  
Resorcinol Formaldehyde ◽  
Scientific Investigations ◽  
Rubber Compounds ◽  
Brittle Layer ◽  
Cure Time ◽  
Rubber Part ◽  
Peel Adhesion ◽  
Peel Force

Abstract The adhesion between virgin textile cords and rubber is always weak, because of significant differences between fiber and rubber in modulus, elongation, polarity as well as reactivity. In order to improve the adhesion, it is customary to use adhesive systems, which act as bridges between elastomer and reinforcement. These are commonly based on Resorcinol/Formaldehyde/Latex (RFL) dips. For polyester and aramid fibers, two dip systems are applied. The first one is an epoxy pre-dip and the second dip is a RFL dip again. Although several mechanisms are proposed to explain the role of RFL, the majority of these explanations are based on assumptions rather than proper scientific investigations. In this paper an attempt is made to understand the role of the rubber vulcanization system on RFL-to-rubber bonding as judged by measuring the H-pullout force, Strap Peel Adhesion Force (SPAF) and the mechanical properties of the compounds. A positive correlation is found between the optimum cure time (t90) of the rubber compounds and the pullout and peel force. In literature this is commonly explained by the lack of curative migration from the rubber into the dip when t90 is low. In the present paper curative migration is monitored by scanning electron microscopy coupled to an energy dispersive X-ray spectrometer (SEM-EDX). A strong enrichment of curatives in the RFL dip near the interface is observed. A high accelerator loading results in a low t90 of the rubber compound as well as a more pronounced enrichment of curatives in the dip near the interface. Therefore the drop in adhesion does not occur because of lack of curative migration from rubber to the RFL layer, but more likely due to overcure of the latex in the dip, causing a brittle layer resulting in low pullout and peel strengths.

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