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Fulltext Permanent deformation investigation of rubber polymer modified binder in superpave hot mix asphalt mixture

Ekarizan Shaffie1, Ahmad Kamil Arshad, Ramadhansyah Putra Jaya, Khairil Azman Masri, Wardati Hashim

Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2020;8(1):45-52.
MyJurnal

Moisture susceptibiltiy is one of the common types of pavement failure found in asphaltic pavements.
Climatic factor such as temperature and moisture has a profound effect on the durability of hot mix
asphalt pavements. Couple with high traffic loads/stresses made stripping of pavement materials
inevitable. Thus, it has become necessary to improve the efficiency of the design of hot mix asphalt
(HMA) for better performance and safe riding comfort. This study investigates and discusses the findings
on the stripping performance of dense graded Superpave mixes using two type of binder; un-modified
binder and rubber polymer modified binder (RPM) using Superpave mix design (AASHTO TP4)
procedure. The RPM binder consists of 4% of both rubber crumb and EVA polymer. Modified Lottman
and Resilient Modulus tests were used to evaluate the stripping performance in these mixtures and this
study also documents the effect of different temperature on tensile strength ratio (TSR) and resilient
modulus ratio (RMR) on the HMA mixtures. Experimental evidences show that the RPM binder mixes
were found to have significantly improved the resistance to moisture damage compared to unmodified
binder mixtures. The RPM binder application may able to alleviate problems related to aggregate
stripping and potholes on our road. Statistical analysis showed good correlation between resilient
modulus and tensile strength ratio.

Matched MeSH terms: Rubber
Fulltext Gamma irradiation influence on mechanical, thermal and conductivity properties of hybrid carbon nanotubes/montmorillonite nanocomposites

Tarawneh MA, Saraireh SA, Chen RS, Ahmad SH, Al-Tarawni MAM, Yu LJ

Radiat Phys Chem Oxf Engl 1993, 2021 Feb;179:109168.
PMID: 33100612 DOI: 10.1016/j.radphyschem.2020.109168

A thermoplastic elastomer (TPE) based nanocomposite with the same weight ratio of hybrid nanofillers composed of carbon nanotubes (CNTs) and montmorillonite nanoclay (DK4) was prepared using a melt blending technique with an internal mixer. The TPE composite was blended from polylactic acid (PLA), liquid natural rubber (LNR) as a compatibilizer and natural rubber (NR) in a volume ratio of 70:10:20, respectively. The weight ratio of CNTs and DK4 was 2.5 wt%. The prepared samples were exposed to gamma radiation at range of 0-250 kGy. After exposure to gamma radiation, the mechanical, thermo-mechanical, thermal and electrical conductivity properties of the composites were significantly higher than unirradiated TPE composites as the irradiation doses increased up to 150 kGy. Transmission electron microscopy (TEM) micrographs revealed the good distribution and interaction between the nano-fillers and the matrix in the prepared TPE hybrid nanocomposites. In summary, the findings from this work definite that gamma irradiation might be a viable treatment to improve the properties of TPE nanocomposite for electronic packaging applications.

Matched MeSH terms: Rubber
Fulltext Treatment of rubber wastewater using zinc sulphate as coagulants-data collection on removal efficiency for physicochemical and heavy metal parameters

Alkarkhi AFM, Amr SSA, Alqaraghuli WAA, Özdemir Y, Zulkifli M, Mahmud MN

Data Brief, 2021 Feb;34:106685.
PMID: 33409347 DOI: 10.1016/j.dib.2020.106685

This article provides data regarding the performance of zinc sulphate as a coagulant for treating rubber industry wastewater. The effect of four factors on removal efficiency of nine parameters is investigated, namely: pH, mixing speed, dosage of coagulant (zinc sulphate) and retention time. Response surface methodology was used to investigate the effect of selected variables. The data obtained from face centered composite design (FCCD) were analyzed by using analysis of variance (ANOVA) and regression model to find the optimum operating conditions for the selected factors.

Matched MeSH terms: Rubber
Fulltext I-Tag: Patients stretcher innovation as a solution to injured patients mobilization

Kim Sooi Law, Noor Khairiah A. Karim, Noor Khairiah A. Karim, Nor Samsinar Abu Talib, Norhaliza Abd Hamid, Nur Arzuar Abdul Rahim, et al.

Jurnal Inovasi Malaysia, 2020;3(2):100-107.
MyJurnal

The paramedic team of Advanced Medical and Dental Institute (IPPT), Universiti Sains Malaysia (USM) is often involved in providing medical assistance for various activities organised by the university such as during PIMPIN siswa outdoor training and sport events. Paramedics often faced difficulty in saving injured patients as the current stretcher is rather heavy (5.8 kg) and is not able to be folded to a smaller size. To overcome this problem, i-TAG, a stretcher made of durable two-layer canvas cloth with the size of 170.0 cm x 74.0 cm and equipped with 10 user-friendly rubber handle, has been invented. The upper part of the stretcher has a zip to insert the spinal board if the victim has spinal and head injuries. The i-TAG is also very light with only 1.2 kg in weight, easy to be folded and stored in emergency bags, and can be easily carried by paramedics. The i-TAG innovative product has a positive impact on health and safety services. Using i-TAG, the task to carry patients or injured victims becomes easier, faster, saves energy and subsequently increases the efficacy of the rescue and medical aid tasks by paramedics.

Matched MeSH terms: Rubber
Fulltext Free-Radical Photopolymerization of Acrylonitrile Grafted onto Epoxidized Natural Rubber

Whba R, Su'ait MS, Tian Khoon L, Ibrahim S, Mohamed NS, Ahmad A

Polymers (Basel), 2021 Feb 23;13(4).
PMID: 33672185 DOI: 10.3390/polym13040660

The exploitation of epoxidized natural rubber (ENR) in electrochemical applications is approaching its limits because of its poor thermo-mechanical properties. These properties could be improved by chemical and/or physical modification, including grafting and/or crosslinking techniques. In this work, acrylonitrile (ACN) has been successfully grafted onto ENR- 25 by a radical photopolymerization technique. The effect of (ACN to ENR) mole ratios on chemical structure and interaction, thermo-mechanical behaviour and that related to the viscoelastic properties of the polymer was investigated. The existence of the -C≡N functional group at the end-product of ACN-g-ENR is confirmed by infrared (FT-IR) and nuclear magnetic resonance (NMR) analyses. An enhanced grafting efficiency (~57%) was obtained after ACN was grafted onto the isoprene unit of ENR- 25 and showing a significant improvement in thermal stability and dielectric properties. The viscoelastic behaviour of the sample analysis showed an increase of storage modulus up to 150 × 103 MPa and the temperature of glass transition (Tg) was between -40 and 10 °C. The loss modulus, relaxation process, and tan delta were also described. Overall, the ACN-g-ENR shows a distinctive improvement in characteristics compared to ENR and can be widely used in many applications where natural rubber is used but improved thermal and mechanical properties are required. Likewise, it may also be used in electronic applications, for example, as a polymer electrolyte in batteries or supercapacitor.

Matched MeSH terms: Rubber
Fulltext Chitosan Epoxidized Natural Rubber Biocomposites for Sorption and Biodegradability Studies

Raju G, Mas Haris MRH, Azura AR, Ahmed Mohamed Eid AM

ACS Omega, 2020 Nov 10;5(44):28760-28766.
PMID: 33195929 DOI: 10.1021/acsomega.0c04081

The slow-release mechanism of copper into soil followed by soil biodegradation was studied using the chitosan (CTS)/epoxidized natural rubber (ENR) biocomposite. The biocomposite was prepared by homogenizing CTS in ENR50 (ENR with about 50% epoxy content) latex in the presence of curing agents and acetic acid. It was found that the adsorption property of the biocomposite was very much influenced by chitosan loading, where 20phrCTS-t-ENR biocomposite can absorb 76.31% of Cu(II) ions. The desorption study indicates that the copper (II) ion can be released at a very slow and control phase as proven by the kinetic study using zero-order, first-order, Higuchi, and Korsmeyer Peppas equations. The slow-release studies comply with the Higuchi square-root equation, indicating that the release process is diffusion-controlled. Results of desorption and biodegradation process suggest that this biocomposite has the potential use of being a slow-release matrix in the field of agriculture.

Matched MeSH terms: Rubber
Fulltext Preparation and Characterization of Low-Molecular-Weight Natural Rubber Latex via Photodegradation Catalyzed by Nano TiO₂

Ibrahim S, Othman N, Sreekantan S, Tan KS, Mohd Nor Z, Ismail H

Polymers (Basel), 2018 Nov 01;10(11).
PMID: 30961141 DOI: 10.3390/polym10111216

Natural rubber is one of the most important renewable biopolymers used in many applications due to its special properties that cannot be easily mimicked by synthetic polymers. To sustain the existence of natural rubber in industries, modifications have been made to its chemical structure from time to time in order to obtain new properties and to enable it to be employed in new applications. The chemical structure of natural rubber can be modified by exposure to ultraviolet light to reduce its molecular weight. Under controlled conditions, the natural rubber chains will be broken by photodegradation to yield low-molecular-weight natural rubber. The aim of this work was to obtain what is known as liquid natural rubber via photodegradation, with titanium dioxide nanocrystals as the catalyst. Titanium dioxide, which was firstly synthesized using the sol⁻gel method, was confirmed to be in the form of an anatase, with a size of about 10 nm. In this work, the photodegradation was carried out in latex state and yielded low-molecular-weight natural rubber latex of less than 10,000 g/mol. The presence of hydroxyl and carbonyl groups on the liquid natural rubber (LNR) chains was observed, resulting from the breaking of the chains. Scanning electron microscopy of the NR latex particles showed that titanium dioxide nanocrystals were embedded on the latex surface, but then detached during the degradation reaction.

Matched MeSH terms: Rubber
Fulltext Sensor application for soil treatment and behaviour

Syahrul Affandi Saidi, Syarifah Idrus Sofia Syed Mohd Yamin, Mohd Sharizan Md Sarip, Wan Azani Mustafa

Journal of Advanced Research in Applied Sciences and Engineering Technology, 2018;13(1):8-15.
MyJurnal

In Malaysia, it is estimated that almost 80 percent of the world's population today used palm oil in their daily lives. Malaysia is the second country exporting palm oil, about 39 percent of world palm oil output. Besides that, Malaysia also recorded about 44 per cent of world exports, making the palm industry very important for countries other than rubber and cocoa. However, to keep the palm industry running smoothly and constantly, there are many challenges to face. One is to maintain soil fertility because the soil can affect the growth of oil palm trees. With the use of this system, it will show the condition of soil behaviour to the farmer about the treatment given. Arduino board is used in this project which it is programmed to calculate and display the level of soil condition by using temperature sensor and soil moisture sensors as an input. This sensor will detect the level of soil moisture and temperature and it is easier for farmers to monitor the soil conditions. Controlled soil conditions can improve the soil's ability to maintain the fertility of palm trees and help plant growth suit to the weather and local climate.

Matched MeSH terms: Rubber
Fulltext Performance Evaluation of Modified Rubberized Concrete Exposed to Aggressive Environments

M Mhaya A, Baghban MH, Faridmehr I, Huseien GF, Abidin ARZ, Ismail M

Materials (Basel), 2021 Apr 11;14(8).
PMID: 33920340 DOI: 10.3390/ma14081900

Recycling of the waste rubber tire crumbs (WRTCs) for the concretes production generated renewed interest worldwide. The insertion of such waste as a substitute for the natural aggregates in the concretes is an emergent trend for sustainable development towards building materials. Meanwhile, the enhanced resistance of the concrete structures against aggressive environments is important for durability, cost-saving, and sustainability. In this view, this research evaluated the performance of several modified rubberized concretes by exposing them to aggressive environments i.e., acid, and sulphate attacks, elevated temperatures. These concrete (12 batches) were made by replacing the cement and natural aggregate with an appropriate amount of the granulated blast furnace slag (GBFS) and WRTCs, respectively. The proposed mix designs' performance was evaluated by several measures, including the residual compressive strength (CS), weight loss, ultrasonic pulse velocity (UPV), microstructures, etc. Besides, by using the available experimental test database, an optimized artificial neural network (ANN) combined with the particle swarm optimization (PSO) was developed to estimate the residual CS of modified rubberized concrete after immersion one year in MgSO4 and H2SO4 solutions. The results indicated that modified rubberized concrete prepared by 5 to 20% WRTCs as a substitute to natural aggregate, provided lower CS and weight lose expose to sulphate and acid attacks compared to control specimen prepared by ordinary Portland cement (OPC). Although the CS were slightly declined at the elevated temperature, these proposed mix designs have a high potential for a wide variety of concrete industrial applications, especially in acid and sulphate risk.

Matched MeSH terms: Rubber
Fulltext Physicochemical characterization and rheological properties of magnetic elastomers containing different shapes of corroded carbonyl iron particles

Burhannuddin NL, Nordin NA, Mazlan SA, Aziz SAA, Kuwano N, Jamari SKM, et al.

Sci Rep, 2021 Jan 13;11(1):868.
PMID: 33441824 DOI: 10.1038/s41598-020-80539-z

Carbonyl iron particles (CIPs) is one of the key components in magnetic rubber, known as magnetorheological elastomer (MRE). Apart from the influence of their sizes and concentrations, the role of the particle' shape is pronounced worthy of the attention for the MRE performance. However, the usage of CIPs in MRE during long-term applications may lead to corrosion effects on the embedded CIPs, which significantly affects the performance of devices or systems utilizing MRE. Hence, the distinctions between the two types of MRE embedded in different shapes of spherical and plate-like CIPs, at both conditions of non-corroded and corroded CIPs were investigated in terms of the field-dependent rheological properties of MRE. The plate-like shape was produced from spherical CIPs through a milling process using a rotary ball mill. Then, both shapes of CIPs individually subjected to an accelerated corrosion test in diluted hydrochloric (HCl) at different concentrations, particularly at 0.5, 1.0, and 1.5 vol.% for 30 min of immersion time. Eight samples of CIPs, including non-corroded for both CIPs shapes, were characterized in terms of a morphological study by field emission scanning electron microscope (FESEM) and magnetic properties via vibrating sample magnetometer (VSM). The field-dependent rheological properties of MREs were analyzed the change in the dynamic modulus behavior of MREs via rheometer. From the application perspective, this finding may be useful for the system to be considered that provide an idea to prolong the performance MRE by utilizing the different shapes of CIPs even when the material is fading.

Matched MeSH terms: Rubber
Effects of Running Surface Stiffness on Three-Segment Foot Kinematics Responses with Different Shod Conditions

Abdul Yamin NAA, Basaruddin KS, Salleh AF, Salim MS, Wan Muhamad WZA

Appl Bionics Biomech, 2021;2021:8842591.
PMID: 33603827 DOI: 10.1155/2021/8842591

Objective: The aim of this study was to investigate the effects of surface stiffness on multisegment foot kinematics and temporal parameters during running.
Methods: Eighteen male subjects ran on three different surfaces (i.e., concrete, artificial grass, and rubber) in both heeled running shoes (HS) and minimal running shoes (MS). Both these shoes had dissimilar sole profiles. The heeled shoes had a higher sole at the heel, a thick base, and arch support, whereas the minimal shoes had a flat base sole. Indeed, the studied biomechanical parameters responded differently in the different footwear during running. Subjects ran in recreational mode speed while 3D foot kinematics (i.e., joint rotation and peak medial longitudinal arch (MLA) angle) were determined using a motion capture system (Qualysis, Gothenburg, Sweden). Information on stance time and plantar fascia strain (PFS) was also collected.
Results: Running on different surface stiffness was found to significantly affect the peak MLA angles and stance times for both HS and MS conditions. However, the results showed that the joint rotation angles were not sensitive to surface stiffness. Also, PFS showed no relationship with surface stiffness, as the results were varied as the surface stiffness was changed.
Conclusion: The surface stiffness significantly contributed towards the effects of peak MLA angle and stance time. These findings may enhance the understanding of biomechanical responses on various running surfaces stiffness in different shoe conditions.

Matched MeSH terms: Rubber
Fulltext Studies on Leaf Venation in Selected Taxa of the Genus Ficus L. (Moraceae) in Peninsular Malaysia

Badron UH, Talip N, Mohamad AL, Affenddi AE, Juhari AA

Trop Life Sci Res, 2014 Dec;25(2):111-25.
PMID: 27073603 MyJurnal

A study on the variation of leaf venation patterns was conducted on 21 taxa of the genus Ficus in Peninsular Malaysia. The results showed the existence of eight leaf venation patterns based on veinlets, the ultimate marginal and areolar venation. The majority of species, such as F. annulata, F. benghalensis, F. benjamina, F. deltoidea var. angustifolia, F. deltoidea var. kunstleri, F. depressa, F. elastica, F. hispida, F. microcarpa, F. religiosa, F. tinctoria, F. ucinata and F. vasculosa, show tri-veinlets. The others exhibit the following: bi-veinlets in F. aurata and F. heteropleura; uni-veinlets in F. lepicarpa, F. schwarzii and F. superba; and simple veinlets in F. aurantiacea and F. fulva. F. sagittata presents no veinlets for areolar venation. The presence of tracheid or swollen veins at the centre of the lamina and the presence of cystolith cells and trichomes are common anatomical characteristics that could assist in group classification of the studied species. Variations in leaf venation patterns are not only valuable in identifying a taxon group, but can also be used to differentiate between species in the genus Ficus.

Matched MeSH terms: Rubber
Fulltext Effect of high silica loading on uncured properties of epoxidised natural rubber compounds

Mazlina, M.K., Che Su, M.S.

ASM Science Journal, 2012;6(1):31-37.
MyJurnal

A 'green tyre' concept has the advantage of low rolling resistance, improved wet grip and enhanced handling. It has been reported that 3% decrease in rolling resistance is equivalent to 1% fuel saving, thus giving the 'green tyre' economic benefits and customer satisfaction. In this study, epoxidised natural rubber (ENR) compounds containing various loading of silica filler were prepared. The processibility and viscoelastic properties were investigated using the rubber processing analyser and Mooney viscometer. Results showed that the properties were adversely affected by the poor dispersion of silica as supported by the bound rubber measurement. In addition, a reversion in the cure behaviour was also observed as the curing temperature was increased to 170ºC.

Matched MeSH terms: Rubber
Fulltext Vulcanisation and coagulant dipping of epoxidised natural rubber latex

Dazylah Darji, Ma'zam Md Said

Pertanika Journal of Science & Technology, 2010;18(2):-.
MyJurnal

Epoxidised Natural Rubber (ENR) is now a commercially available polymer produced by chemical modification of natural rubber. Currently, three types of ENR are commercially available, and these are ENR 10, ENR 25, and ENR 50 with 10%, 25%, and 50% mol epoxidation, respectively. Studies on prevulcanisation of ENR 50 and postvulcanisation of the latex films were carried out. The objective of this study was to develop ENR 50 that could be dipped easily in coagulant dipping solution to produce dipped products. Several attempts were made by compounding prevulcanised ENR 50 at various sulphur levels ranging from 0.5 to 3.0 pphr. Using suitable coagulant dipping systems, ENR 50 film could be formed despite the high contents of non-ionic surfactant. It was found that the tensile strength of prevulcanised ENR 50 film decreased with the increase in the sulphur level. The results show that as level of sulphur increased, M300 also increased to an optimum value of 1.5 pphr of sulphur. For the postvulcanised ENR 50 film, however, the tensile strength increased and then decreased with the increasing sulphur level. Meanwhile M300 increased with the increasing postvulcanization time and sulphur level. The postvulcanisation of ENR 50 film seems to be a more effective way of increasing tensile properties than by prevulcanisation of ENR 50.

Matched MeSH terms: Rubber
Fulltext Detection of pipeline intelligent gauge jammed in pipeline by neutron device

Md Fakarudin Ab Rahman, Ismail Mustapha, Nor Pa’iza Mohd Hasan, Ibrahim, Pairu

Jurnal Sains Nuklear Malaysia, 2012;24(2):35-41.
MyJurnal

In industrial plants such as electricity generating, petroleum, chemical and petrochemical plants, pipelines are used extensively to transport liquid from one location to another. In radiation vulcanization of natural rubber latex (RVNRL) plants, pipelines are also used to transport latex to storage tank. During one of its maintenance activities, a pipeline intelligent gauge (PIG) that was used to monitor pipe integrity jammed inside the pipe causing interruption to its operation or loading activities. Sealed source technology was utilized to determine the location of jammed PIG in the pipeline. Fast neutrons from a 50 mCi Americium Beryllium (AmBe241), with energy range between 0.5 to11 MeV, were used for the study. Helium 3 (He3) detector was used to detect slow neutrons having a range of energy of 30 eV- 0.5 MeV. The investigation was carried out using neutron backscatter technique scanner. By adopting back-scattered technique, the location of jammed PIG in the pipeline has been successfully determined.

Matched MeSH terms: Rubber
Fulltext Effect of epoxidized natural rubber on mechanical properties of epoxy reinforced kenaf fibre composites

Abu Bakar, M.A., Ahmad, S., Kuntjoro, W.

Pertanika Journal of Science & Technology, 2012;20(1):129-137.
MyJurnal

Kenaf fibre that is known as Hibiscus cannabinus, L. family Malvaceae is an herbaceous plant that can be grown under a wide range of weather conditions. The uses of kenaf fibres as a reinforcement material in the polymeric matrix have been widely investigated. It is known that epoxy has a disadvantage of brittleness and exhibits low toughness. In this research, liquid epoxidized natural rubber (LENR) was introduced to the epoxy to increase its toughness. Kenaf fibres, with five different fibre loadings of 5%, 10%, 15%, 20% and 25% by weight, were used to reinforce the epoxy resins (with and without addition of epoxidized natural rubber) as the matrices. The flexural strength, flexural modulus and fracture toughness of the rubber toughened epoxy reinforced kenaf fibre composites were investigated. The results showed that the addition of liquid epoxidized natural rubber (LENR) had improved the flexural modulus, flexural strength and fracture toughness by 48%, 30%, and 1.15% respectively at 20% fibre loading. The fractured surfaces of these composites were investigated by using scanning electron microscopic (SEM) technique to determine the interfacial bonding between the matrix and the fibre reinforcement.

Matched MeSH terms: Rubber
Fulltext Some remarks on diurnal radon concentration at various locations in Peninsular Malaysia

Ahmad Saat, Zaini Hamzah, Zaharidah Abu Bakar, Zuraidah A. Munir, Siti Mariam Sumari, Misbah Hassan

Journal of Nuclear and Related Technologies, 2010;2010(1):49-57.
MyJurnal

A study was carried out to determine short term diurnal radon concentration at five locations in Malaysia. Two locations (KG & AP) are former tin mining areas that has been converted to housing area and training centre respectively, one a relatively new city (SA), that was formerly a rubber and oil palm plantation area, one older cities (KB) and one housing complex by the sea (LP). The study was carried out in 2005, 2006 and 2007 using a diffused-junction photodiode sensor continuous radon monitor. The monitor is recognized by the USEPA. In each location, measurements were carried out on at least ten sites. Former tin mining areas of KG and AP shows up to seven times higher indoor average than the average in the other three locations. However the indoor average in all locations is still below the action level of 4 pCiL-1. For outdoor, the former tin mining areas average concentration was higher than the global average of 0.4 pCiL-1. For the twenty four hours temporal variation the trend indicated that former tin mining areas concentration are always higher, and at time up to six fold higher. The hourly variation of all locations follows an identical trend of high concentration during early to late morning and drop in the afternoon till evening. The outdoor twenty four hour temporal average of former tin mining areas is consistently higher than the outdoor global average of 0.4 pCiL-1. The strong correlation between indoor and outdoor concentration at AP, indicates that indoor radon might originates from outdoor environment. The study was also extended to estimate the effective dose (mSvyr-1) of Rn-222 to the public.

Matched MeSH terms: Rubber
Fulltext Effect of crumb rubber on the fresh properties of mortar and concrete

Noor, N.M., Ahmad, M.H., Othman, N.H.

Pertanika Journal of Science & Technology, 2017;25(105):245-250.
MyJurnal

The importance of the performance of concrete cannot be neglected since it is the early indicator of its physical and mechanical properties. It became more important when material with different physical properties than normal material such as rubber tire was used as concrete constituent. This paper presented apart of research result conducted on mortar and concrete with crumb rubber. Crumb rubber was replaced at 10%, 15% and 20% as sand replacement by volume. In addition, ordinary Portland cement was added to silica fume at 10% and 15% by weight. The properties measured in this study are air content and workability test. As for workability, superplasticizers were constantly used at 1% dosage for all mortar mixture, and 0.5% to 0.7% for concrete mixture. The air content was set at 4% to 6% and mortar flow test was conducted on a steel plate, shocked 15 times in 15 seconds and concrete slump test was carried out using slump cone equipment. Pressure method was used to measure air content. All mixes were done in a controlled room temperature. Results showed that when CR was added in the mixture segregation was observed in mortar requiring a high dose of superplasticizer to be added to improve the workability while air-modifying agent was used to reduce the mortar air content. In concrete mixture, low dosage of superplasticizers was required for workability and air-entrained agent was injected into the mixture to increase the air content between 4%-6%.

Matched MeSH terms: Rubber
Fulltext Development of adjustable foot corrective device for clubfoot treatment

Shahrol Mohamaddan, Chai Siew Fu, Ahmad Hata Rasit, Siti Zawiah Md Dawal, Keith Case

Pertanika Journal of Science & Technology, 2017;25(105):251-258.
MyJurnal

Congenital talipes equinovarus (CTEV) or clubfoot is a complex deformity of the foot that is characterised by four main deformities; forefoot cavus and adductus, hindfoot varus and ankle equinus. Currently, the Ponseti method is the most general and recognized treatment with a high success rate of over 90%. The treatment involves gentle manipulation and serial casting. However, the casting method could create complications for the patients such as soft-tissue damage and inconvenience in following the treatment schedule especially for those living far away from hospital. The aim of this research is to develop an adjustable corrective device for clubfoot treatment based on the techniques in the Ponseti method and at the same time attempt to eliminate the side-effects. The prototype consists of six adjustable movements from six different mechanisms to correct the four deformities. The prototype was developed using 3D printing method and the main material used is polylactic acid (PLA), rubber, aluminium and cotton fabric with sponge. The total weight of the prototype is around 300 g.

Matched MeSH terms: Rubber
Fulltext Energy absorption and morphological characteristics of opened-cell green rubber foam at different recycled carbon fiber loading

Mazliah, M., Noraiham, M., Anisah, A.L., Azrul, Y., Hairul, E.A.M., Jeefferie, A.R., et al.

Malaysian Journal of Microscopy, 2015;11(1):56-60.
MyJurnal

Incineration and disposal of carbon fiber waste from the aircraft industry lead to serious energy consumption and environmental pollution. The use of this waste as reinforcement is a wise approach to appreciate the high performance of the carbon fiber. This study is part of our effort to develop new green rubber foam from recycled carbon fiber prepreg (rCFP) reinforced natural rubber via internal mixer. It is focusing on the effect of different rCFP loading at 1, 3, 5, and 7 parts per hundred rubbers (phr) as reinforcement. The samples were prepared by melt compounding using an internal mixer and expanded via two step heat transfer foaming process. The physical properties of the green rubber foam were characterized and the results were observed to systematically correlate with the impact properties of the foam. The absorbed energy of the foam increases up to 0.3 joules with increasing relative foam density of 0.81 which is associated with the formation of smaller foam cells ~0.68mm and more spherical shape pores.

Matched MeSH terms: Rubber

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