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An integrative taxonomic review of the agamid genus Bronchocela (Kuhl, 1820) from Peninsular Malaysia with descriptions of new montane and insular endemics

Grismer LL, Wood PL, Lee CH, Quah ES, Anuar S, Ngadi E, et al.

Zootaxa, 2015 Apr 20;3948(1):1-23.
PMID: 25947760 DOI: 10.11646/zootaxa.3948.1.1

An integrative taxonomic analysis is used to identify and describe two new species of the agamid genus Bronchocela (Kuhl) from Peninsular Malaysia: an upland species B. shenlong sp. nov. from Bukit Larut, Perak in the Bintang Mountain Range and Parit Falls, Cameron Highlands, Pahang in the Titiwangsa Mountain Range and an insular species, B. rayaensis sp. nov., from Pulau Langkawi, Kedah off the northwest coast on the border with Thailand. Both species are diagnosed from each other and all other species of Bronchocela on the basis of body shape, scale morphology, and color pattern. The analysis also demonstrates the remarkable genetic similarity of B. cristatella (Kuhl) throughout 1120 km of its range from northern Peninsular Malaysia to western Borneo despite its highly variable coloration and pattern. The two new species are appended to a rapidly growing list of newly described lizard species (60 to date) from Peninsular Malaysia tallied within the last decade.
Prognostic Implications of Dual Platelet Reactivity Testing in Acute Coronary Syndrome

de Carvalho LP, Fong A, Troughton R, Yan BP, Chin CT, Poh SC, et al.

Thromb. Haemost., 2018 02;118(2):415-426.
PMID: 29443374 DOI: 10.1160/TH17-08-0564

Studies on platelet reactivity (PR) testing commonly test PR only after percutaneous coronary intervention (PCI) has been performed. There are few data on pre- and post-PCI testing. Data on simultaneous testing of aspirin and adenosine diphosphate antagonist response are conflicting. We investigated the prognostic value of combined serial assessments of high on-aspirin PR (HASPR) and high on-adenosine diphosphate receptor antagonist PR (HADPR) in patients with acute coronary syndrome (ACS). HASPR and HADPR were assessed in 928 ACS patients before (initial test) and 24 hours after (final test) coronary angiography, with or without revascularization. Patients with HASPR on the initial test, compared with those without, had significantly higher intraprocedural thrombotic events (IPTE) (8.6 vs. 1.2%, p ≤ 0.001) and higher 30-day major adverse cardiovascular and cerebrovascular events (MACCE; 5.2 vs. 2.3%, p = 0.05), but not 12-month MACCE (13.0 vs. 15.1%, p = 0.50). Patients with initial HADPR, compared with those without, had significantly higher IPTE (4.4 vs. 0.9%, p = 0.004), but not 30-day (3.5 vs. 2.3%, p = 0.32) or 12-month MACCE (14.0 vs. 12.5%, p = 0.54). The c-statistic of the Global Registry of Acute Coronary Events (GRACE) score alone, GRACE score + ASPR test and GRACE score + ADPR test for discriminating 30-day MACCE was 0.649, 0.803 and 0.757, respectively. Final ADPR was associated with 30-day MACCE among patients with intermediate-to-high GRACE score (adjusted odds ratio [OR]: 4.50, 95% confidence interval [CI]: 1.14-17.66), but not low GRACE score (adjusted OR: 1.19, 95% CI: 0.13-10.79). In conclusion, both HASPR and HADPR predict ischaemic events in ACS. This predictive utility is time-dependent and risk-dependent.
Fulltext An assessment of Stuart's transport medium in the diagnosis of gonorrhoea

Lee CH, Ngeow YF

Med J Malaysia, 1983 Mar;38(1):23-6.
PMID: 6633329

Genital discharge from patients unth. smear positive gonorrhoea was transported from the clinic to the laboratory in. Stuart's transport medium (Oxoid CM 111). Within. six hours of transit time the recovery rate of gonococci was 94%. When compared with "bedside" inoculation onto Modified Thayer Martin medium, there was no significant difference in recovery rates up to 6 hours of transportation in Stuart's transport medium, However, the rate of isolation of gonococci was significantly reduced after 20 to 30 hours of transportation. It is concluded that Stuart's transport medium is an acceptable transport medium for specimens containing gonococci when specimens reach the laboratory within 6 hours of collection.
Fulltext Primary breast tuberculosis (TB) in a patient with known invasive breast carcinoma: A case report

Lee CH, Sharif SZ

Med J Malaysia, 2016 Jun;71(3):149-51.
PMID: 27495893 MyJurnal

Breast tuberculosis (TB) is rare even in endemic countries. Most of these cases occur as secondary TB due to a concurrent infection. Primary breast TB is diagnosed when it is the only site of disease without other foci of infection. The presentation of primary breast TB may often mimic carcinoma of the breast. While imaging is not specific, histopathology provides a definitive diagnosis. Here, we present a case of primary breast TB in a breast cancer patient and review the literature.
Detection of Chlamydia trachomatis in urine samples by polymerase chain reaction and enzyme immunoassay

Ngeow YF, Hema V, Zakaria M, Lee CH, Ramachandran S

Malays J Pathol, 1997 Dec;19(2):127-32.
PMID: 10879253

First-void urine samples collected from sexually transmitted diseases (STD) clinic patients were examined by a nested polymerase chain reaction (PCR) and a commercial enzyme immunoassay (IDEIA Chlamydia) for the diagnosis of Chlamydia trachomatis urethritis or cervicitis. The primers for the PCR amplified a target in the major outer membrane protein (MOMP) gene in C trachomatis while the IDEIA detected genus-specific chlamydial lipopolysaccharide. Discrepant results were resolved by retesting urine specimens with a second (plasmid-based) PCR and taking urethral or endocervical swab results into consideration. For 231 men (chlamydial prevalence 20.4%), the sensitivity, specificity, positive and negative predictive values were 59.6%, 99.5%, 96.6% and 90.6% for urine IDEIA, 68.1%, 99.5%, 97% and 92.4% for urethral swab IDEIA and 97.9%, 99.5%, 97.9% and 99.5% for urine PCR. The corresponding rates for 66 women (chlamydial prevalence 54.6%) were 19.4%, 100%, 100% and 50.8% for urine IDEIA, 86.1%, 96.7%, 96.9% and 85.3% for endocervical swab IDEIA and 91.7%, 93.3%, 94.3% and 90.3% for urine PCR. Hence, in a high prevalence population, the urine IDEIA was a suitable alternative to the male urethral swab IDEIA but significantly less sensitive than the endocervical swab IDEIA. The urine PCR was, however, much more sensitive than the urine IDEIA for both men and women and could replace the endocervical swab IDEIA for the diagnosis of chlamydial cervicitis.
Perceived Social Support and Life Satisfaction of Malaysian Chinese Young Adults: The Mediating Effect of Loneliness

Gan SW, Ong LS, Lee CH, Lin YS

J Genet Psychol, 2020 08 13;181(6):458-469.
PMID: 32787705 DOI: 10.1080/00221325.2020.1803196

This paper examined the role of loneliness in mediating the relation between social support and life satisfaction among Chinese young adults within the Malaysian context. Young adults (N = 275; Mage = 22.41; SD = 1.76; 57.5% females) completed self-administered questionnaires on the scales of perceived social support, loneliness and life satisfaction. The results of Structural Equation Modeling (SEM) showed a partial mediation effect of loneliness on the relation between social support and life satisfaction. The integration of the bottom-up theory of subjective well-being and social cognitive theory is included to explain the mediating process. The results revealed that perceived social support can relate to a lower level of loneliness, which could eventually lead to higher levels of young adults' life satisfaction. Overall, the findings highlighted the importance of social support as well as their loneliness as a mediating pathway in promoting Malaysian Chinese young adults' life satisfaction. Interventions are also suggested to optimize life satisfaction as a whole.
Fulltext Betel-quid dependence and oral potentially malignant disorders in six Asian countries

Lee CH, Ko AM, Yen CF, Chu KS, Gao YJ, Warnakulasuriya S, et al.

Br J Psychiatry, 2012 Nov;201(5):383-91.
PMID: 22995631 DOI: 10.1192/bjp.bp.111.107961

Despite gradual understanding of the multidimensional health consequences of betel-quid chewing, information on the effects of dependent use is scant.
Melt volume flow rate and melt flow rate of kenaf fibre reinforced Floreon/magnesium hydroxide biocomposites

Lee CH, Sapuan SM, Lee JH, Hassan MR

Springerplus, 2016;5(1):1680.
PMID: 27733982

A study of the melt volume flow rate (MVR) and the melt flow rate (MFR) of kenaf fibre (KF) reinforced Floreon (FLO) and magnesium hydroxide (MH) biocomposites under different temperatures (160-180 °C) and weight loadings (2.16, 5, 10 kg) is presented in this paper. FLO has the lowest values of MFR and MVR. The increment of the melt flow properties (MVR and MFR) has been found for KF or MH insertion due to the hydrolytic degradation of the polylactic acid in FLO. Deterioration of the entanglement density at high temperature, shear thinning and wall slip velocity were the possible causes for the higher melt flow properties. Increasing the KF loadings caused the higher melt flow properties while the higher MH contents created stronger bonding for higher macromolecular chain flow resistance, hence lower melt flow properties were recorded. However, the complicated melt flow behaviour of the KF reinforced FLO/MH biocomposites was found in this study. The high probability of KF-KF and KF-MH collisions was expected and there were more collisions for higher fibre and filler loading causing lower melt flow properties.
Continuous positive airway pressure and adverse cardiovascular events in obstructive sleep apnea: are participants of randomized trials representative of sleep clinic patients?

Reynor A, McArdle N, Shenoy B, Dhaliwal SS, Rea SC, Walsh J, et al.

Sleep, 2022 Apr 11;45(4).
PMID: 34739082 DOI: 10.1093/sleep/zsab264

STUDY OBJECTIVES: Randomized controlled trials (RCTs) have shown no reduction in adverse cardiovascular (CV) events in patients randomized to continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea (OSA). This study examined whether randomized study populations were representative of OSA patients attending a sleep clinic.
METHODS: Sleep clinic patients were 3,965 consecutive adults diagnosed with OSA by in-laboratory polysomnography from 2006 to 2010 at a tertiary hospital sleep clinic. Characteristics of these patients were compared with participants of five recent RCTs examining the effect of CPAP on adverse CV events in OSA. The percentage of patients with severe (apnea-hypopnea index, [AHI] ≥ 30 events/h) or any OSA (AHI ≥ 5 events/h) who met the eligibility criteria of each RCT was determined, and those criteria that excluded the most patients identified.
RESULTS: Compared to RCT participants, sleep clinic OSA patients were younger, sleepier, more likely to be female and less likely to have established CV disease. The percentage of patients with severe or any OSA who met the RCT eligibility criteria ranged from 1.2% to 20.9% and 0.8% to 21.9%, respectively. The eligibility criteria that excluded most patients were preexisting CV disease, symptoms of excessive sleepiness, nocturnal hypoxemia and co-morbidities.
CONCLUSIONS: A minority of sleep clinic patients diagnosed with OSA meet the eligibility criteria of RCTs of CPAP on adverse CV events in OSA. OSA populations in these RCTs differ considerably from typical sleep clinic OSA patients. This suggests that the findings of such OSA treatment-related RCTs are not generalizable to sleep clinic OSA patients.Randomized Intervention with Continuous Positive Airway Pressure in CAD and OSA (RICCADSA) trial, https://clinicaltrials.gov/ct2/show/NCT00519597, ClinicalTrials.gov number, NCT00519597.Usefulness of Nasal Continuous Positive Airway Pressure (CPAP) Treatment in Patients with a First Ever Stroke and Sleep Apnea Syndrome, https://clinicaltrials.gov/ct2/show/NCT00202501, ClinicalTrials.gov number, NCT00202501.Effect of Continuous Positive Airway Pressure (CPAP) on Hypertension and Cardiovascular Morbidity-Mortality in Patients with Sleep Apnea and no Daytime Sleepiness, https://clinicaltrials.gov/ct2/show/NCT00127348, ClinicalTrials.gov number, NCT00127348.Continuous Positive Airway Pressure (CPAP) in Patients with Acute Coronary Syndrome and Obstructive Sleep Apnea (OSA) (ISAACC), https://clinicaltrials.gov/ct2/show/NCT01335087, ClinicalTrials.gov number, NCT01335087.
Fulltext Acute myocardial infarction in young Asian women: a comparative study on Chinese, Malay and Indian ethnic groups

Xie CB, Chan MY, Teo SG, Low AF, Tan HC, Lee CH

Singapore Med J, 2011 Nov;52(11):835-9.
PMID: 22173254

There is a paucity of data on acute myocardial infarction (AMI) in young Asian women and of comparative data among various ethnic groups with respect to risk factor profile and clinical outcomes. We present a comprehensive overview of the clinical characteristics of young Asian women with AMI and a comparative analysis among Chinese, Malay and Indian women in a multi-ethnic Asian country.
Fulltext Technologies for Assessment of Motor Disorders in Parkinson's Disease: A Review

Oung QW, Muthusamy H, Lee HL, Basah SN, Yaacob S, Sarillee M, et al.

Sensors (Basel), 2015 Aug 31;15(9):21710-45.
PMID: 26404288 DOI: 10.3390/s150921710

Parkinson's Disease (PD) is characterized as the commonest neurodegenerative illness that gradually degenerates the central nervous system. The goal of this review is to come out with a summary of the recent progress of numerous forms of sensors and systems that are related to diagnosis of PD in the past decades. The paper reviews the substantial researches on the application of technological tools (objective techniques) in the PD field applying different types of sensors proposed by previous researchers. In addition, this also includes the use of clinical tools (subjective techniques) for PD assessments, for instance, patient self-reports, patient diaries and the international gold standard reference scale, Unified Parkinson Disease Rating Scale (UPDRS). Comparative studies and critical descriptions of these approaches have been highlighted in this paper, giving an insight on the current state of the art. It is followed by explaining the merits of the multiple sensor fusion platform compared to single sensor platform for better monitoring progression of PD, and ends with thoughts about the future direction towards the need of multimodal sensor integration platform for the assessment of PD.
Fulltext Effect of Empty Fruit Brunch reinforcement in PolyButylene-Succinate/Modified Tapioca Starch blend for Agricultural Mulch Films

Ayu RS, Khalina A, Harmaen AS, Zaman K, Mohd Nurrazi N, Isma T, et al.

Sci Rep, 2020 01 24;10(1):1166.
PMID: 31980742 DOI: 10.1038/s41598-020-58278-y

In this study, it focused on empty fruit brunch (EFB) fibres reinforcement in polybutylene succinate (PBS) with modified tapioca starch by using hot press technique for the use of agricultural mulch film. Mechanical, morphological and thermal properties were studied. Mechanical analysis showed decreased in values of modulus strength for both tensile and flexural testing for fibres insertion. Higher EFB fibre contents in films resulted lower mechanical properties due to poor fibre wetting from insufficient matrix. This has also found evident in SEM micrograph, showing poor interfacial bonding. Water vapour permeability (WVP) shows as higher hydrophilic EFB fibre reinforcement contents, the rate of WVP also increase. Besides this, little or no significant changes on thermal properties for composite films. This is because high thermal stability PBS polymer show its superior thermal properties dominantly. Even though EFB fibres insertion into PBS/tapioca starch biocomposite films have found lower mechanical properties. It successfully reduced the cost of mulch film production without significant changes of thermal performances.
Fulltext Mechanical Strength, Thermal Conductivity and Electrical Breakdown of Kenaf Core Fiber/Lignin/Polypropylene Biocomposite

Ahmad Saffian H, Talib MA, Lee SH, Md Tahir P, Lee CH, Ariffin H, et al.

Polymers (Basel), 2020 Aug 15;12(8).
PMID: 32824275 DOI: 10.3390/polym12081833

Mechanical strength, thermal conductivity and electrical breakdown of polypropylene/lignin/kenaf core fiber (PP/L/KCF) composite were studied. PP/L, PP/KCF and PP/L/KCF composites with different fiber and lignin loading was prepared using a compounding process. Pure PP was served as control. The results revealed that tensile and flexural properties of the PP/L/KCF was retained after addition of lignin and kenaf core fibers. Thermal stability of the PP composites improved compared to pure PP polymer. As for thermal conductivity, no significant difference was observed between PP composites and pure PP. However, PP/L/KCF composite has higher thermal diffusivity. All the PP composites produced are good insulating materials that are suitable for building. All PP composites passed withstand voltage test in air and oil state as stipulated in IEC 60641-3 except PP/L in oil state. SEM micrograph showed that better interaction and adhesion between polymer matrix, lignin and kenaf core fibers was observed and reflected on the better tensile strength recorded in PP/L/KCF composite. This study has successfully filled the gap of knowledge on using lignin and kenaf fibers as PP insulator composite materials. Therefore, it can be concluded that PP/Lignin/KCF has high potential as an insulating material.
Fulltext Importance of Interfacial Adhesion Condition on Characterization of Plant-Fiber-Reinforced Polymer Composites: A Review

Lee CH, Khalina A, Lee SH

Polymers (Basel), 2021 Jan 29;13(3).
PMID: 33573036 DOI: 10.3390/polym13030438

Plant fibers have become a highly sought-after material in the recent days as a result of raising environmental awareness and the realization of harmful effects imposed by synthetic fibers. Natural plant fibers have been widely used as fillers in fabricating plant-fibers-reinforced polymer composites. However, owing to the completely opposite nature of the plant fibers and polymer matrix, treatment is often required to enhance the compatibility between these two materials. Interfacial adhesion mechanisms are among the most influential yet seldom discussed factors that affect the physical, mechanical, and thermal properties of the plant-fibers-reinforced polymer composites. Therefore, this review paper expounds the importance of interfacial adhesion condition on the properties of plant-fiber-reinforced polymer composites. The advantages and disadvantages of natural plant fibers are discussed. Four important interface mechanism, namely interdiffusion, electrostatic adhesion, chemical adhesion, and mechanical interlocking are highlighted. In addition, quantifying and analysis techniques of interfacial adhesion condition is demonstrated. Lastly, the importance of interfacial adhesion condition on the performances of the plant fiber polymer composites performances is discussed. It can be seen that the physical and thermal properties as well as flexural strength of the composites are highly dependent on the interfacial adhesion condition.
A Comprehensive Review on Advanced Sustainable Woven Natural Fibre Polymer Composites

Aisyah HA, Paridah MT, Sapuan SM, Ilyas RA, Khalina A, Nurazzi NM, et al.

Polymers (Basel), 2021 Feb 02;13(3).
PMID: 33540731 DOI: 10.3390/polym13030471

Over the last decade, the progressive application of natural fibres in polymer composites has had a major effect in alleviating environmental impacts. Recently, there is a growing interest in the development of green materials in a woven form by utilising natural fibres from lignocellulosic materials for many applications such as structural, non-structural composites, household utilities, automobile parts, aerospace components, flooring, and ballistic materials. Woven materials are one of the most promising materials for substituting or hybridising with synthetic polymeric materials in the production of natural fibre polymer composites (NFPCs). These woven materials are flexible, able to be tailored to the specific needs and have better mechanical properties due to their weaving structures. Seeing that the potential advantages of woven materials in the fabrication of NFPC, this paper presents a detailed review of studies related to woven materials. A variety of factors that influence the properties of the resultant woven NFRC such as yarn characteristics, fabric properties as well as manufacturing parameters were discussed. Past and current research efforts on the development of woven NFPCs from various polymer matrices including polypropylene, polylactic acid, epoxy and polyester and the properties of the resultant composites were also compiled. Last but not least, the applications, challenges, and prospects in the field also were highlighted.
Fulltext Potential for Natural Fiber Reinforcement in PLA Polymer Filaments for Fused Deposition Modeling (FDM) Additive Manufacturing: A Review

Lee CH, Padzil FNBM, Lee SH, Ainun ZMA, Abdullah LC

Polymers (Basel), 2021 Apr 27;13(9).
PMID: 33925266 DOI: 10.3390/polym13091407

In this review, the potential of natural fiber and kenaf fiber (KF) reinforced PLA composite filament for fused deposition modeling (FDM) 3D-printing technology is highlighted. Additive manufacturing is a material-processing method in which the addition of materials layer by layer creates a three-dimensional object. Unfortunately, it still cannot compete with conventional manufacturing processes, and instead serves as an economically effective tool for small-batch or high-variety product production. Being preformed of composite filaments makes it easiest to print using an FDM 3D printer without or with minimum alteration to the hardware parts. On the other hand, natural fiber-reinforced polymer composite filaments have gained great attention in the market. However, uneven printing, clogging, and the inhomogeneous distribution of the fiber-matrix remain the main challenges. At the same time, kenaf fibers are one of the most popular reinforcements in polymer composites. Although they have a good record on strength reinforcement, with low cost and light weight, kenaf fiber reinforcement PLA filament is still seldom seen in previous studies. Therefore, this review serves to promote kenaf fiber in PLA composite filaments for FDM 3D printing. To promote the use of natural fiber-reinforced polymer composite in AM, eight challenges must be solved and carried out. Moreover, some concerns arise to achieve long-term sustainability and market acceptability of KF/PLA composite filaments.
Fulltext A Review on Properties and Application of Bio-Based Poly(Butylene Succinate)

Rafiqah SA, Khalina A, Harmaen AS, Tawakkal IA, Zaman K, Asim M, et al.

Polymers (Basel), 2021 Apr 29;13(9).
PMID: 33946989 DOI: 10.3390/polym13091436

Researchers and companies have increasingly been drawn to biodegradable polymers and composites because of their environmental resilience, eco-friendliness, and suitability for a range of applications. For various uses, biodegradable fabrics use biodegradable polymers or natural fibers as reinforcement. Many approaches have been taken to achieve better compatibility for tailored and improved material properties. In this article, PBS (polybutylene succinate) was chosen as the main topic due to its excellent properties and intensive interest among industrial and researchers. PBS is an environmentally safe biopolymer that has some special properties, such as good clarity and processability, a shiny look, and flexibility, but it also has some drawbacks, such as brittleness. PBS-based natural fiber composites are completely biodegradable and have strong physical properties. Several research studies on PBS-based composites have been published, including physical, mechanical, and thermal assessments of the properties and its ability to replace petroleum-based materials, but no systematic analysis of up-to-date research evidence is currently available in the literature. The aim of this analysis is to highlight recent developments in PBS research and production, as well as its natural fiber composites. The current research efforts focus on the synthesis, copolymers and biodegradability for its properties, trends, challenges and prospects in the field of PBS and its composites also reviewed in this paper.
Fulltext Thermal, Physical and Mechanical Properties of Poly(Butylene Succinate)/Kenaf Core Fibers Composites Reinforced with Esterified Lignin

Saffian HA, Yamaguchi M, Ariffin H, Abdan K, Kassim NK, Lee SH, et al.

Polymers (Basel), 2021 Jul 19;13(14).
PMID: 34301116 DOI: 10.3390/polym13142359

In this study, Kraft lignin was esterified with phthalic anhydride and was served as reinforcing filler for poly(butylene succinate) (PBS). Composites with different ratios of PBS, lignin (L), modified lignin (ML) and kenaf core fibers (KCF) were fabricated using a compounding method. The fabricated PBS composites and its counterparts were tested for thermal, physical and mechanical properties. Weight percent gain of 4.5% after lignin modification and the FTIR spectra has confirmed the occurrence of an esterification reaction. Better thermo-mechanical properties were observed in the PBS composites reinforced with modified lignin and KCF, as higher storage modulus and loss modulus were recorded using dynamic mechanical analysis. The density of the composites fabricated ranged from 1.26 to 1.43 g/cm3. Water absorption of the composites with the addition of modified lignin is higher than that of composites with unmodified lignin. Pure PBS exhibited the highest tensile strength of 18.62 MPa. Incorporation of lignin and KCF into PBS resulted in different extents of reduction in tensile strength (15.78 to 18.60 MPa). However, PBS composite reinforced with modified lignin exhibited better tensile and flexural strength compared to its unmodified lignin counterpart. PBS composite reinforced with 30 wt% ML and 20 wt% KCF had the highest Izod impact, as fibers could diverge the cracking propagation of the matrix. The thermal conductivity value of the composites ranged from 0.0903 to 0.0983 W/mK, showing great potential as a heat insulator.
Fulltext Effects of Fabric Counts and Weave Designs on the Properties of Laminated Woven Kenaf/Carbon Fibre Reinforced Epoxy Hybrid Composites

Aisyah HA, Paridah MT, Khalina A, Sapuan SM, Wahab MS, Berkalp OB, et al.

Polymers (Basel), 2018 Nov 28;10(12).
PMID: 30961245 DOI: 10.3390/polym10121320

The effects of different fabric materials namely weave designs (plain and satin) and fabric counts (5 × 5 and 6 × 6) on the properties of laminated woven kenaf/carbon fibre reinforced epoxy hybrid composites were evaluated. The hybrid composites were fabricated from two types of fabric, i.e., woven kenaf that was made from a yarn of 500tex and carbon fibre, by using vacuum infusion technique and epoxy resin as matrix. The panels were tested for tensile, flexural, and impact strengths. The results have revealed that plain fabric is more suitable than satin fabric for obtaining high tensile and impact strengths. Using a fabric count of 5 × 5 has generated composites that are significantly higher in flexural modulus as compared to 6 × 6 which may be attributed to their structure and design. The scanned electron micrographs of the fractured surfaces of the composites demonstrated that plain woven fabric composites had better adhesion properties than satin woven fabric composites, as indicated by the presence of notably lower amount of fibre pull out.
Fulltext The Challenges and Future Perspective of Woven Kenaf Reinforcement in Thermoset Polymer Composites in Malaysia: A Review

Lee CH, Khalina A, Nurazzi NM, Norli A, Harussani MM, Rafiqah SA, et al.

Polymers (Basel), 2021 Apr 25;13(9).
PMID: 33922885 DOI: 10.3390/polym13091390

In this review, the challenges faced by woven kenaf thermoset polymer composites in Malaysia were addressed with respect to three major aspects: woven kenaf reinforcement quality, Malaysian citizen awareness of woven kenaf thermoset composite products, and government supports. Kenaf plantations were introduced in Malaysia in the last two decades, but have generally not produced much kenaf composite product that has been widely accepted by the public. However, woven kenaf fiber enhances the thermoset composites to a similar degree or better than other natural fibers, especially with respect to impact resistance. Woven kenaf composites have been applied in automotive structural studies in Malaysia, yet they are still far from commercialization. Hence, this review discusses the kenaf fiber woven in Malaysia, thermoset and bio-based thermoset polymers, thermoset composite processing methods and, most importantly, the challenges faced in Malaysia. This review sets guidelines, provides an overview, and shares knowledge as to the potential challenges currently faced by woven kenaf reinforcements in thermoset polymer composites, allowing researchers to shift their interests and plans for conducting future studies on woven kenaf thermoset polymer composites.

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