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Kapok fiber is a natural hollow fiber that has superior biocompatibility and biodegradability and is naturally antibacterial. Because of its unique properties, it has great potential in the application of postoperative repair dressings. The wettability and micro-equilibrium of kapok fibers play a critical role in dressing applications. In this study, the critical adhesion volume and adhesion energy of essence liquid to alkali-treated kapok fiber (AKF) were quantitatively calculated to explore the wettability and micro-equilibrium through the equilibrium wetting theory. Meanwhile, the three-phase contact line (TCL) structure was described. The results showed that the critical adhesion volumes of the three types of essence liquid for AKF were 3.45, 3.81, and 4.12 μL, respectively. Moreover, the critical volumes and low error rates derived from the equilibrium wetting theory were 3.41 μL and 1.16%, 3.99 μL and 4.51%, and 4.60 μL and 10.43%, respectively. Therefore, the critical volume of adhesion could be well calculated by the theoretical model. The average adhesive energies of essence liquid to the AKF were 0.38, 0.45, and 0.56 J, respectively, caused by the difference in liquids properties. The TCL showed a mechanical lock and bonding points at both ends because of the curvature difference and higher surface energy. These results are proposed to inspire the design of a liquid carrier of kapok fibers based on the fiber network structure.

Utilization of natural biopolymers has shown potential in generating innovations for tissue engineering applications. This study aims to fabricate scaffolds from cellulose acetate derived from kapok fiber. Cellulose is extracted from raw kapok fibers by alkali treatment and delignification then synthesized into cellulose acetate. Kapok cellulose acetate (KCA) is dissolved in dimethyl sulfoxide to fabricate the scaffold. Materials were characterized using Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR) spectrometer, X-ray diffractometer (XRD) and Differential Scanning Calorimeter (DSC). FTIR analysis has shown that cellulose was extracted from kapok and cellulose acetate was successfully synthesized. XRD analysis also confirmed the presence of cellulose acetate. Results have also shown that synthesized KCA seems to have higher crystallinity than commercially available cellulose acetate (CCA). The degree of substitution (DS) of KCA was found to be 2.85 which is close to the DS value of tri-substituted cellulose acetate. DSC analysis has shown lower glass transition temperature of 52.15°C but higher degradation temperature of 300.43°C than the CCA. Moreover, the values for the enthalpy of fusion for two endotherms of KCA (44.0556 J/g and 18.6946 J/g) are higher than the values for CCA by 344% and 261%, respectively; thus, indicating the higher degree of crystallinity for synthesized KCA samples.

Kapok fiber as a natural sorbent with excellent hydrophobic-oleophilic characteristic was studied. The effect of temperature on oil sorption behavior and wettability of kapok fiber powder was quant...

Kapok fiber is emerging as a cheaper natural fiber having excellent thermal insulation properties. Recycled polyester/kapok blended needle punched nonwoven waddings are prepared where the effect of...

In the production of functional nonwovens with sustainable fibers, kapok, with unique qualities, becomes an excellent candidate for the production of thermal insulation textiles. However, the devel...

In this study, kapok fiber powder (KFP) was evaluated as a wicking material for the application of mechanical lubricants. KFP had lengths ranging from several microns to 2 mm, with part of the hollow lumen being compressed. Experiments showed that the oil sorption capacity of KFP for mineral oil and PAO4 was 21.9 g/g, and 19.9 g/g, respectively. The oil release behavior of oil-impregnated KFP was quantitatively evaluated by a device proposed in the present study to simulate the usage of lubricant in bearings. The results indicated a two-step oil release process including a rapid release phase and a slow release phase. The cumulative oil release increased with an increasing oil/fiber ratio and temperature. The release mechanism of oil-impregnated KFP was further investigated by release kinetics models which demonstrated that the oil release followed Fickian diffusion and could be described by the Rigter–Peppas model. These results are proposed to provide a reference for the evaluation of the oil release performance of oil-impregnated wicking materials when they are applied in mechanical bearing field.

Kapok fiber with high degree of hollow and small fiber diameter has excellent sound absorption. To optimize the sound absorption characters at the low frequency, sound absorption coefficients and specific surface impedance of two-layer, three-layer, and four-layer materials as polyethylene film-reinforced kapok fiber nonwoven fabrics have been studied by using the impedance tube method in the frequency range of 100–2500 Hz. The layering sequence, the polyethylene films thickness, and the gradient thickness structure of nonwoven fabrics affected the sound absorption properties at the low frequency for multi-layer materials that have been analyzed. The results show that the multi-layer composite materials have better sound absorption than a single-layer nonwoven fabrics at the low frequency. The elastic vibration of polyethylene film contributes to sound absorption improvement at the low frequency. The sound absorption at the low frequency of multi-layer materials can be further improved by changing polyethylene film position or increasing polyethylene film thickness. In addition, the gradient thickness structure of nonwoven fabrics can effectively improve sound absorption at the low frequency, and the gradient change direction also exhibits remarkable effects on the sound absorption of multi-layer materials.

This work evaluated the effects of cold plasma treatment on kapok fibers (Ceiba pentandra L.). Fourier-transform infrared (FTIR) spectra showed changes in characteristic absorption bands, indicating modification of the chemical composition of the fiber. Surface roughness, observed by field-emission gun scanning electron microscope (FEG-SEM), increased. Furthermore, the water uptake was significantly affected, the ability to uptake oil increased and a mechanism of reaction was suggested. The thermal behavior, analyzed by thermogravimetric analysis (TGA), was slightly altered and it was also shown that fiber surface was activated by the plasma treatment. Ultimately, cold plasma may prove as a feasible approach to improve fiber-matrix adhesion for the production of biodegradable polymer composites. Keywords: Kapok fiber, Cold plasma treatment, Kinetic studies, Surface activation.

Self-propelled micro- and nanomotors are a current research focus and have shown attractive potential in environmental applications. Here, we report a biomass approach to construct a novel tubular micromotor decorated with a nanozyme/natural enzyme hybrid, which integrated the advantages of the self-propelled movement, selectivity of a natural enzyme and catalytic activity of artificial nanozymes. Such a micromotor had a unique hierarchical structure where laccase immobilized-Fe-BTC MOF nanoparticles grew uniformly on Mn2O3–NiFe2O4 nanosheets, which was constructed using natural kapok fiber as a template. This laccase-integrated Fe-BTC/NiFe2O4 micromotor was capable of self-propulsion with a speed of 120 μm s−1 by oxygen bubbles via the decomposition of H2O2 catalyzed by Mn2O3. Owing to the incorporation of autonomous motion with high selectivity of natural laccase and high peroxidase-like activity of the Fe-BTC/NiFe2O4 nanozyme, these micromotors exhibited much higher catalytic activity to methylene blue degradation than their passive counterparts. Besides as a substrate to accommodate laccase immobilized-Fe-BTC, magnetic NiFe2O4 also enabled the remote magnetic control on the movement direction.

This study used a simple and efficient dipping method to prepare oleophilic calcium stearate-coated kapok fibers (CaSt2-KF) with improved hydrophobicity. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) confirmed the deposition of calcium stearate particles on the surface of the kapok fibers. This led to higher surface roughness and improved static water contact angle of 137.4°. The calcium stearate-coated kapok fibers exhibited comparable sorption capacities for kerosene, diesel, and palm oil. However, the highest sorption capacity of 59.69 g/g was observed for motor oil at static conditions. For motor oil in water, the coated fibers exhibited fast initial sorption and a 65% removal efficiency after 30 s. At equilibrium, CaSt2-KF attained a sorption capacity of 33.9 g/g and 92.5% removal efficiency for motor oil in water. The sorption kinetics of pure motor oil and motor oil in water follows the pseudo-second-order kinetic model, and the Elovich model further described chemisorption. Intraparticle diffusion and liquid film diffusion were both present, with the latter being the predominant diffusion mechanism during motor oil sorption.

A carbon microtube aerogel (CMA) with hydrophobicity, strong adsorption capacity, and superb recyclability was obtained by a feasible approach with economical raw material, such as kapok fiber. The CMA possesses a great adsorption capacity of 78-348 times its weight. Attributed to its outstanding thermal stability and excellent mechanical properties, the CMA can be used for many cycles of distillation, squeezing, and combustion without degradation, which suggests a potential practical application in oil-water separation. In addition, the adsorption capacity still retained 98% by distillation, 97% by squeezing, and 90% by combustion after 10 cycles. Therefore, the obtained CMA has a broad prospect as an economical, efficient, and environmentally friendly adsorbent. National Research Foundation (NRF) This work was financially supported by Singapore National Research Foundation under NRF RF Award No. MOE2016- T2-1-131, Tier 1 2017-T1-001-075.

A facile dipping strategy was performed for roughening the surface of two plant fibers (CGF, Calotropis gigantea fiber; KF, kapok fiber) via nano-sized MoS2 to obtain eco-friendly oil-absorbing materials, MoS2-CGF and MoS2-KF. The results indicated that in addition to the roughened surface topography, MoS2-CGF and MoS2-KF possessed also hydrophobic–oleophilic properties and highly hydrophobic stability to corrosive environments. For twelve selected model oils (including organic solvents), MoS2-roughened fibers had excellent absorption capacity, with the value of 25–100 g/g for MoS2-CGF and 65–135 g/g for MoS2-KF within a few seconds. Furthermore, MoS2-CGF and MoS2-KF exhibited outstanding oil–water selectivity by using trichloromethane and cyclohexane as the model oils. After ten absorption–desorption cycles, a limited reduction in the re-sorption percentage was observed, demonstrating that MoS2-CGF and MoS2-KF had good reusability. By combining the advantages of abundant resource, low cost, high efficiency and environmental friendliness, MoS2-roughened fibers may be promising as efficient oil sorbents for the removal of oil spills in water.

This work was aimed at evaluating the sorption of dispersed oil by kapok fiber. The physicochemical characteristics of kapok fiber were investigated using BET, SEM, FTIR, XRD, contact angle and elemental analysis. The oil droplet size distribution at different temperatures was analysed using a Coulter counter, and its relationship with sorption was investigated. The effects of dosage, hydraulic retention time and temperature, on the sorption performance were studied. The result indicates that the sorption of dispersed oil by kapok fiber is spontaneous, endothermic and agreed with the pseudo-first-order reaction kinetics. The amount of oil that could be removed is about 28.5 %, while that of water is less than 1 % of the original amount (0.5 dm3). Kapok is a promising natural hydrophobic fiber for dispersed oil removal from oily wastewater.

Creating a low-cost, highly efficient, and recyclable superabsorbent for spilled-oil cleanup is of great significance but remains a big challenge. Herein, we report a facile strategy to produce economic, environmentally friendly, and reusable foam from agricultural waste kapok fibers. These kapok-derived cellulose nanofibrils foams (KNFs) demonstrate a hierarchically porous structure at micro-level with ultra-low density (2.7 mg·cm−3). The superhydrophobic KNFs (150.5°) show outstanding oil absorption (126.8–320.4 g·g−1) and oil-water separation performance. Notably, a facile approach is designed to reuse KNFs easily by a homemade oil release system. The release behavior of the KNFs is quantitatively analyzed and confirmed by the Rigter-Peppas model, indicating that the oil release followed the Fickian diffusion. The KNFs exhibit desirable reusability, and can be recycled for at least 50 times while keeping excellent oil absorption, and release performance. These advantages prove that the KNF is a desirable substitute for spilled-oil treatment.

Constructing hierarchical structures is indispensable to tuning the electromagnetic properties of carbon-based materials. Here, carbon microtubes with nanometer wall thickness and micrometer diameter were fabricated by a feasible approach with economical and sustainable kapok fiber. The carbonized kapok fiber (CKF) exhibits microscale pores from the inherent porous templates as well as pyrolysis-induced nanopores inside the wall, affording the hierarchical carbon microtube with excellent microwave absorbing performance over broad frequency. Particularly, CKF-650 exhibits an optimized reflection loss (RL) of −62.46 dB (10.32 GHz, 2.2 mm), while CKF-600 demonstrates an effective absorption bandwidth (RL < −10 dB) of 6.80 GHz (11.20–18.00 GHz, 2.8 mm). Moreover, more than 90% of the incident electromagnetic wave ranging from 2.88 GHz to 18.00 GHz can be dissipated by simply controlling the carbonization temperature of KF and/or the thickness of the carbon-microtube-based absorber. These encouraging findings provide a facile alternative route to fabricate microwave absorbers with broadband attenuation capacity by utilizing sustainable biomass.

Kapok lifi, “ceiba pentandra” olarak da bilinen kapok ağacının meyvesi içerisinde bulunan bir tür tohum lifidir. İçi boş tüp yapısı, hidrofobik/oleofilik karakteri, düşük yoğunluğu ve su üzerinde batmadan yüzebilme kabiliyeti ile bilinen selülozik liflerden farklı bir profil sergileyen kapok lifleri ayrıca kolay ulaşılabilir, yenilenebilir, biyobozunur ve tekrar tekrar kullanılabilir olması ile son yıllarda ilgi gören bir araştırma materyali haline gelmiştir. Kapok lifleri üzerine yapılan araştırmalar, su kaynaklarımıza bulaşan çeşitli yağ türevli atıkların uzaklaştırılmasından, ses ve ısı yalıtımı malzemelerine, biyoyakıttan elektrokimyasal depolama malzemelerine kadar geniş bir alanda kullanım potansiyeline sahip olduğunu hatta bu kullanım yelpazesinin daha da genişleyebileceğini kanıtlar niteliktedir. Sürdürülebilirlik hedefleri altında yenilenebilir alternatif yeşil kaynakların daha fazla dikkat çekmeye başladığı şu günlerde, kapok lifleri oldukça önemli bir ham madde kaynağı olarak ön plana çıkmaktadır. Bu derleme çalışmasında; kapok liflerinin yapısı, özellikleri, uygulama alanları gibi başlıklar detaylı olarak incelenmiştir.

Solar steam generation by heat localization has attracted much attention for its potential in the treatment of wastewater and seawater desalination. However, the preparation of a single-component solar receiver with low cost, simple preparation process, high mechanical strength and energy conversion efficiency is still a challenge. Herein, we report the preparation of kapok fiber-PPy aerogels with superwetting, porous structure, high light absorption, and high mechanical strength via polypyrrole modification of the Ca2+ crosslinked kapok fiber aerogels. The kapok fiber-PPy aerogels show three-dimensional structure with high porosity (94%), excellent light absorption (ca. 97%), low thermal conductivity (0.0241 W m−1 k−1) and high mechanical strength (0.12 MPa under 75% of strain). As a solar steam generation device, a high energy conversion efficiency of 82.4% was achieved under 1 kW m−2 illumination. The findings of this investigation may open a simple and novel route towards the fabrication of a low-cost a single-component biomass-based solar receivers for solar steam generation.

The design of hierarchical structures from biomass has become one of the hottest subjects in the field of microwave absorption due to its low cost, vast availability and sustainability. A kapok-fiber-derived carbon microtube was prepared by facile carbonization, and the relation between the structure and properties of the carbonized kapok fiber (CKF) was systematically investigated. The hollow tubular structures afford the resulting CKF composites with excellent microwave-absorbing performance. The sample with a 30 wt.% loading of CKF in paraffin demonstrates the strongest microwave attenuation capacity, with a minimum reflection loss of −49.46 dB at 16.48 GHz and 2.3 mm, and an optimized effective absorption bandwidth of 7.12 GHz (10.64–17.76 GHz, 2.3 mm) that covers 34% of the X-band and 96% of the Ku-band. Further, more than 90% of the incident electromagnetic wave in the frequency from 4.48 GHz to 18.00 GHz can be attenuated via tuning the thickness of the CKF-based absorber. This study outlines a foundation for the development of lightweight and sustainable microwave absorbers with a high absorption capacity and broad effective absorption bandwidth.

The application of pH-responsive superwetting materials receives increasing attention in oil/water separation. In this work, a mussel inspired robust surface coating fabricated with dopamine, copolymer PDMAEMA-co-PHEMA-co-PHFBMA (PDHH) and SiO2 nanoparticles (DPS) was formed on stainless steel mesh to perform multiple repeatable oil/water separation. Herein, dopamine was chosen to provide strong adhesion strength and durability, endowing the mesh excellent stability in harsh environments, such as mechanical abrasion, acid/alkali immersion and UV irradiation. In virtue of pH stimulation, the as-prepared mesh can be reversibly switched between superhydrophobicity and superhydrophilicity. Moreover, the mesh possesses remarkable oil/water separation efficiency (SE) (≥98%) and desirable recyclability. An oil collector prepared by the mesh and kapok fiber showed good oil absorption capability in the range of 39.67–79.56 g/g. The facile and inexpensive preparation of the durable separation device enables it promising in actual oil/water separation.

High content of oil aerosols exist in the ambient air. In this study, the kapok fiber was studied for removing oil aerosols due to its oleophilic property and large lumen. The influence of the kapok fiber on filtration performance of air filter papers against the di-(2-ethyl hexyl) sebacate (DEHS) oil aerosols was analyzed. Firstly, different contents of kapok fibers were blended with hardwood fibers to make filter papers by the wet-laid process. Then the effects of the kapok fiber content on the morphology, thickness, air permeability, strength tensile and DEHS penetration of filter papers were studied. Finally, the DEHS loading performance of filter papers with different content of kapok fibers was evaluated. The results showed that as the content of the kapok fibers increased, the thickness and air permeability increased. The most penetrating particle size was 200 nm of all the papers and the filtration efficiency decreased as the content of kapok fibers increased. During the loading process, the pressure drop increased slowly in the first stage due to the deposition of the oil aerosols on the surface of the filter papers leading to the rise of the friction area. Then the pressure drop increased faster due to the rearrangement of oil aerosols in the filter papers. Finally, it increased exponentially since the oil aerosols formed bridges and films between the fibers and clogged the papers. It was found that as the content of kapok fibers increased, the loading time of the first and second stages became longer, which meant that the kapok fibers could improve the oil aerosols holding capacity. This study demonstrated the potential of using kapok fibers in air filter for removing oil aerosols.

A superhydrophobic CeO2-modified kapok fiber (SCMKF) was fabricated using CeO2 and octadecyltrimethoxysilane (OTMS) by a simple chemical deposition method. Scanning electron microscopy, Fo...

In this work an attempt has been made to produce kapok/polypropylene (80/20) needle punched nonwoven for oil spill clean-up process. The difficulties involved in structuring kapok fiber through nee...

The hydrophilic kapok fiber was obtained by Fenton reaction via a cost-effective and controllable solution-dipping process. The adsorption performances of Fenton reaction modified kapok fiber (FRKF) were evaluated in terms of pH, time, pollutant concentration, temperature, co-existing anions, and reusability, so as to find the optimum adsorption conditions for removing As(III) and As(V) from the aqueous solution. The results showed that FRKF was stable at a relatively wide range of pH for As(III) and As(V), the optimal pH of As(III) and As(V) were 7.0 and 4.0, respectively, and the adsorption equilibrium time of As(III) was shorter than that of As(V). The effect of temperature on the adsorption of As(III) by FRKF was negligible, but it has an obvious effect on the adsorption of As(V). As the temperature increased from 293 K to 313 K, the adsorption uptakes of FRKF for As(V) increased from 18.7 mg g−1 to 30.0 mg g−1. Compared with N O 3 − , and S O 4 2 − , the co-existing anion of P O 4 3 − has a serious inhibitory effect on the adsorption of arsenic due to its high content of negative charge and a tetrahedral structure similar to As(V). Based on the XPS analysis, the functional groups of hydroxyl and/or carboxyl on FRKF play a major role by forming C-O-As bond with arsenic in the adsorption process. Finally, the adsorption-desorption experiments demonstrated that FRKF has good stability and reusability, thus FRKF can be used an effective and practical adsorbent for the treatment of arsenic or other heavy metals.

This study focused on synthesizing of nanocrystalline cellulose (NCC) from kapok fiber with the combination of chemical and mechanical methods. The as-synthesized NCC is used to produce nanocrystalline cellulose (NCC) paper. It was determined that the optimum condition to synthesis nanocrystalline cellulose (NCC) from kapok fiber using acid hydrolysis process treatment was at 45°C, 2 hours and 50% concentration of H 2SO 4. The particle size of the synthesized nanocrystalline cellulose (NCC) was 262.9 - 455.6 nm. The disappearance of peaks 1731.89, 1594.68, 1505.51 & 1240 cm -1 in the (FTIR) spectroscopy was related to the removal of non-cellulose component such as lignin and hemicellulose. Based on the contact angle, the value gained for that contact angle of the filter paper was increased from 29.650° to 40.261° and 32.002° due to presence of nanocrystalline cellulose (NCC) in the filter paper. It was determined that the modified filter paper with the nanocrystalline cellulose (NCC) had the highest water-resistances property and was considered the most hydrophobic of all the other papers.

This paper is focused on investigating the microstructure of kapok fiber through the observation of residual deformation and fracture morphology of kapok fibers in longitudinal microscopic images. By comparing the morphology of kapok fibers before and after different treatments, unique weak spiral lines inside the cell wall were found. The spiral lines that divide the cell wall into a wound ribbon appear to be the weak locations (e.g., the fracture or bending points) of the fiber. The damage mechanism of kapok fibers in assemblies was summarized. Details of structures inside the ribbon were also examined to reveal that macro-fibrils of 0.2 µm in diameter and >1.0 µm in length were packed neatly along the fiber axial on the surface. A framework of the multi-assembly structure of kapok fiber was summarized.

In this study, kapok/Chop Strand Mat (CSM) reinforced unsaturated polyester hybrid composites were fabricated using hand lay-up method with a boat composite sandwich- configuration laminate method. The glass CSM was used as a shell with kapok as a core, with an approximate total fiber content of 60%. Three different designated layers of kapok and weight ratios of (60/40)% and (40/60)% were used to fabricated for comparison purposes. Fire retardant properties were investigated using UL-94 which are vertical burning and horizontal burning test. The result showed that the hybrid composite with 3 layers of kapok took the longest time to burn. It has proved that the hybrid kapok/CSM reinforced displayed better in fire retardation than the raw CSM composites by using sandwich arrangement. It was found physical properties of kapok reinforced composite showed the increasing trend of water absorption and thickness swelling with the increasing storage time.

Kapok fiber is a natural material that has unique properties, can be renewed with a large lumen, it has hydrophobic properties, as an absorbent in oil, heavy metals, and sound. To increase the absorption capacity of heavy metals, physical properties, and chemical resistance, modifications were made to change the fiber properties from hydrophobic to hydrophilic. One way is through the process of soaking the kapok fibers in a solvent to remove non-cellulose compounds. In this study, to improve the properties of kapok fiber, soaking has been done with various solutions, there are HCl, NaOH, NaClO, NaClO-NaOH-NaClO, and NaClO2-NaOH-NaClO2 solution. Immersion of kapok fibers in NaClO2-NaOH-NaClO2 solution can increase cellulose content up to 93.69% with porosity content of 4.75%. NaClO2-NaOH-NaClO2-treated can absorb water up to 211.27%, the second highest after treatment with the NaClO-NaOH-NaClO-treated solution of 285.29%. Immersion in NaClO-NaOH-NaClO and NaClO2-NaOH-NaClO2 solvents also causes damage to the kapok fiber protective layer which indicates the loss of lignin, so that a significant change of the hydrophobic fiber becomes hydrophilic as seen in the SEM results.

The industrialization of synthetic fiber has resulted in an economic depression for both domestic and global kapok fiber industries as well as the farmers. On the other hand, the development of ssthe oleochemical industry in Indonesia demands a separation process that is less cost- and energy-intensive. Supporting the sustainable development goals (SDGs) number 1, 8, 9, 12, and 13, in this study, the under-tapped kapok fiber has been utilized to show its potential value as an oil sorbent material. Despite having high oil sorption capacity and being biodegradable, the raw kapok fiber has low oil selectivity, low oil retention, and a fragile structure. The kapok fiber has been modified with reduced graphene oxide (rGO) to obtain hydrophobic-oleophilic absorbent with high absorption capacity, high oil selectivity, high oil retention, and strong structure to maximize the recovery yield. Modification has been done by soaking kapok fiber in GO supernatant and reducing them with ascorbic acid, then freeze-drying the fiber to get a robust superhydrophobic sponge. Techno-economic and life-cycle analyses have been conducted and the results indicate that rGO-KF aerogel is economically viable with a potential GPM greater than 36,27%, and environmentally beneficial as it can potentially decrease product carbon emissions by 32.8 tons/ton recovered oil.

Cancer development and chronic diseases are associated with the overexpression of sialoglycans terminated to the surface proteins and lipids of cancer cells compared with normal cells. The isolation and detection of sialoglycopeptides from complex peptides mixture still remain challenges due to their low abundance, low ionization, and losses of sialic acid residues and water molecule during analytical processes. In this study, kapok fiber, a natural fiber derived from the kapok tree (Bombax ceiba L.), has shown excellent capability to specifically and efficiently enrich sialoglycopeptides, without losses of sialic acid residues and water molecule from sialoglycans. The main components on the surface of kapok fiber are syringyl and guaiacyl lignins which play an important role in isolating sialoglycopeptides from complex peptide mixtures.

In order to improve the utilization rate of kapok fiber, flame-retardant and sound-absorption composites were prepared by the hot pressing method with kapok fiber as the reinforced material, poly&epsilon, caprolactone as the matrix material, and magnesium hydroxide as the flame retardant. Then, the effects of hot pressing temperature, hot pressing time, density of composites, mass fraction of kapok fiber, thickness of composites, and air layer thickness on the sound-absorption properties of composites were analyzed, with the average sound absorption coefficient as the index. Under the optimal process parameters, the maximum sound absorption coefficient reached 0.830, the average sound absorption coefficient was 0.520, and the sound-absorption band was wide. Thus, the composites belonged to high-efficiency sound-absorbing material. The flame-retardant effect of magnesium hydroxide on the composites was investigated, and the limiting oxygen index could reach 31.5%. Finally, multifunctional composites based on kapok fiber with flame retardant properties, and sound-absorption properties were obtained.

A hydrophilic kapok fiber was prepared by a chemical process of the Fenton reaction and used as an adsorbent to remove Pb(II) from aqueous solution. The effects of experimental parameters including pH, contact time, Pb(II) concentration, and coexisting heavy metals were estimated as well as evaluated. The optimum concentrations of FeSO4 and H2O2 for the Fenton reaction-modified kapok fiber (FRKF) were 0.5 mol L−1 and 1 mol L−1, respectively. The adsorption kinetic models and isotherm equations of Langmuir and Freundlich were conducted to identify the most optimum adsorption rate and adsorption capacity of Pb(II) on FRKF. The FRKF displayed an excellent adsorption rate for Pb(II) in single metal solution with the maximum adsorption capacity of 94.41 ± 7.56 mg g−1 at pH 6.0. Moreover, the FRKE still maintained its adsorption advantage of Pb(II) in the mixed metal solution. The FRKF exhibited a considerable potential in removal of metal content in wastewater streams.

Kapok fiber was one of the natural cellulosic fiber that can be found widely in Asia’s forest especially in Indonesia. Kapok fiber was short and smooth surface causing poor inter-fiber cohesion that could not be processed in spinning. This fiber could be utilized to be accoustic sound proofing material. This research investigated about absorptive properties of non woven kapok fiber (SK) and its layered combination with tricot knitted fabric (TC) and double weave fabric (DWK). Combination of various kind of fabric’s type improved thickness and air cavity that impact absorptive properties of fabric. Impedance tube were used to characterization sound absorptive properties at low until normal frequency on 100 until 5000 Hz. The optimum sound absorptive were showed by combination of non woven kapok fiber with double weave fabric with thicknes 11,25 mm. It shows thickness impact to air cavity and gave significant effect to sound absorptive properties.

An oil recovery system composed of an oil capture module packed kapok fibers and a vacuum pump was developed for continuous oil recovery from artificial oil/water (O/W) mixture. The mechanism of porous hydrophobic–oleophilic kapok fiber layer (KFL) for O/W separation was analyzed, and a physical model for continuous oil recovery process was established. The oil recovery performance, which was evaluated by oil recovery rate (ORR, %) and oil enrichment rate (OER, %), depended on turbulence intensity of O/W mixture, driving pressure, KFL porosity and thickness, initial oil content of O/W mixture, and oil viscosity. Owing to the well oil selectivity of kapok, the oil content of the permeate was above 95.0% when the initial oil content of the O/W mixture was between 6.0% and 8.0%. The system was capable of collecting low viscosity oil efficiently.

In this study, the sound-absorption properties of kapok fiber nonwoven fabrics were investigated in the frequency region of 100–2500 Hz using the impedance tube method. The effects of physical parameters including fiber mixing ratio, bulk density, and thickness on sound-absorption properties of composites were studied. The comparisons of kapok fiber with polypropylene fiber and hollow polyester fiber indicated that as a natural fiber, kapok fiber had superior acoustical properties at low frequency. A new simple model had been developed to predict the sound absorption coefficient of kapok fiber nonwoven composites at low frequency.

Kapok fiber corresponds to the seed hairs of the kapok tree (Ceiba pentandra), and is a typical cellulosic fiber with the features of thin cell wall, large lumen, low density and hydrophobic–oleophilic properties. As a type of renewable natural plant fiber, kapok fiber is abundant, biocompatible and biodegradable, and its full exploration and potential application have received increasing attention in both academic and industrial fields. Based on the structure and properties of kapok fiber, this review provides a summary of recent research on kapok fiber including chemical and physical treatments, kapok fiber-based composite materials, and the application of kapok fiber as an absorbent material for oils, metal ions, dyes, and sound, with special attention to its use as an oil-absorbing material, one predominant application of kapok fiber in the coming future.

A sound absorption model of kapok-based fiber nonwoven fabrics, based on the Biot–Allard model, has been developed by considering the heat conduction performance of the materials and the limpness of the fiber frame. Comparisons of sound absorption coefficients and specific surface impedance calculated by the Biot–Allard model and the new model with the measured values for four different kinds of kapok-based fiber nonwoven fabrics have been made. It is shown that the new model provides better predictions than the Biot–Allard model. The new model may be the theoretical foundation for the design of industrial products for kapok materials.

The feasibility of the industrial application of kapok fiber for the removal of lead (II) ions from aqueous stream was evaluated in this study. The fiber was modified using NaOH solution and also was oxidized with NaClO2 solution. Both of the chemically enhanced kapok fibers showed a high adsorption efficiency, which was 23.4 and 34.6 mg/g, respectively, while unmodified kapok fibers had 4.70 mg/g. Kinetic reactions and their rate constants exhibited that the removal of lead was linearly correlated with adsorption capacity of the modified and oxidized kapok fibers. Adsorption isotherm of the experiment fitted very well with the Langmuir model for the chemically enhanced kapok fibers. Adsorption capacity decreased with a decrease in the pH. The recycling process of the used kapok fibers was also carried out and the results found that kapok fibers were reusable with relatively high regeneration rate.

Kapok fiber is a natural hollow fiber whose assemblies show high oil sorption capacity for various oils. In this article, a dual-scale model based on Washburn Capillary Theory was developed to study the oil sorption behavior of kapok assemblies with relation of their pore structure. The validity of this model was evaluated by oil sorption coefficient obtained from the curve of oil mass increase versus sorption time, which was measured by a wicking method. Diesel and motor oil were chosen as experimental oils. It turned out that theoretical values of sorption coefficients of the two oils were highly consistent with their experimental results. On the basis of theoretical analysis, we found that the big lumen of kapok fiber contributed considerably to the oil sorption capacity of kapok assembly, which was further enhanced with increasing kapok packing density. At the tightly packed condition of 0.10 g/cm 3 , oil absorbed by kapok lumens accounted for up to one fifth of the total oil absorption of kapok assembly for both test oils.

The natural hollow fiber, namely kapok, has been studied for the removal of oil, particularly in the area of oil spill clean-up. The hydrophobic nature of the natural absorbent has been demonstrated to exhibit (or show potential to exhibit) excellent oil absorption properties. Kapok fiber is inexpensive, readily available, very lightweight which makes it easy for transportation and its excellent buoyancy eases retrieval. Reusability of the material up to 15 cycles has been reported and this supports its being environmental-friendly. This paper looks into the oil absorption capacity of raw kapok fiber that can be dramatically enhanced by the simple mechanism of stirring. The oil absorption capacity is greatly increased to more than 200 times the mass of kapok used, i.e., with stirring, 1 g of the kapok fiber is able to absorb at least 200 g of the oil (200 g/g) which in this case is the refined palm oil used for cooking. The paper also discusses the reasons for the improvement due to stirring. And as a natural agricultural product which is abundant, besides being environmental-friendly, its application would be a sustainable approach to control water pollution due to oil spills and industrial organic contaminants.

The kapok fibers which are the functional fiber materials having natural hollows are environment friendly materials the demand and interest of which are increasing. The kapok fibers are environment friendly and natural hollow fibers which are 5-8 times lighter than cottons and have excellent performances in thermo keeping property, air permeability, bulkiness and resilience. In this study, the pretreatment according to the dyeing behaviors of kapok fibers were studied. Pretreatment(scouring, bleaching) were a variety of conditions. Scouring and bleaching, images of changed surfaces and cross-sections and dyeing behaviors of the dye-o-meter according to the concentration measured in meters and compared. Although the final exhaustion ratio of the kapok fibers scoured with a high concentration recipe was almost as same as that of the kapok fibers bleached with a high concentration recipe, the initial absorption speed of the kapok fibers scoured with the high concentration recipe was faster than that of the kapok fibers bleached with the high concentration recipe.

As a natural fiber, kapok fiber has the high hollow degree that is very good for sound absorption. Four different kinds of kapok-based fiber nonwoven fabrics, made by kapok fiber mixing with hollow polyester, viscose fiber, PP fiber and cotton fiber respectively, were made and the sound absorption coefficients were measured in the frequency region of 100 - 6300 Hz by using a two-microphone transfer-function method. The comparisons of the sound absorption for four types of materials with similar thickness and densities with no air gap and with 1 cm, 3 cm air gap were made. The results indicate that the sound absorption of kapok/hollow polyester fiber nonwoven fabrics is superior to those of other three ones and kapok/hollow polyester fiber nonwoven fabrics can be used for sound-absorbing materials in engineering.

Kapok fiber is a kind of cellulosic fiber harvested from the kapok fruit and has many unique properties and potential applications owing to its high degree of hollowness. It is important to understand the mechanical properties of the kapok fiber under transverse compression because its hollow structure can be squashed easily. In this research, kapok fibers were carded slightly to form a kapok fibrous assembly (KFA) in which the fibers were straightened and parallel. A KFA was considered as an approximately isotropic matrix material in the transverse direction. The fiber arrangement in a KFA was geometrically modeled with a pipe-piling structure. The viscoelastoplastic model and its constitutive equations were established to characterize the mechanical response of the KFA under transverse compression. Three compressional stages (A – the viscoelastic stage, from the initial point 0 to the yielding point 1; B – the viscoelastoplastic stage, from the yielding point 1 to the point 2; and C – the senior viscoelastic stage, from the yielding point 2 to the point at the maximum compressional load) were observed from the stress–strain curve, and four parameters were determined to describe the elastic, viscoelastic, and viscoplastic behaviors under each compression cycle performed on the Instron compression tester. The results indicate that the variable elasticity of the KFAs exists throughout the total compression, viscoelasticity appeared only in stage C, and the viscoplastic property was evident in stage B. The KFAs did not exhibit viscoelastic behavior in stages A and B because the viscoelastic element of the Kelvin model failed to work in these two stages. The influence of conditioning humidity on the parameters was also investigated.

Kapok fiber is light, buoyant, and excellent in thermal insulation because of its high degree of hollowness. However, it is difficult to preserve the lumen structure of kapok fiber under repetitive compression in the course of manufacturing and utilization, and then the fiber may lose its unique features quickly. Thus, it is critical to know the resilience of kapok under repeated compression and how it can be affected by environmental factors. In this paper, we studied the compressional resilience of fibrous assemblies made of slightly carded kapok fibers by using an Instron compression tester. The nonlinear compressional behavior of the assemblies was observed in the repeated transverse compressing cycles with a constant compressional strain, and three characteristic stages of the entire compressing cycles—linear elastic, metamorphosis, and densification—were identified. The plastic and the visco-elasto-plastic compressional deformations were characterized from the compressional stress–strain curve. It was found that the conditioning humidity and the number of compressing cycles could affect the compressional resilience of the kapok fibrous assembly, and that the dry-treated kapok fibrous assemblies possessed better resilience and higher strains than the wet-treated ones.

Kapok fiber has a unique large thin-walled hollow structure, lightweight and water repellent oil of excellent features, and is not yet fully exploited the small breed natural fibers. In the development process of the use of kapok fiber, there is a problem of dyeing, finishing, dyeing rate, dyeing and poor. Plasma processing technique is a modification to the fiber surface, non-polluting promising new technologies and has energy efficient. The research kapok fiber after plasma surface modification, found kapok modified staining rate has been significantly improved absorbent; Modified kapok fiber mechanical properties are not changed significantly; While exploring the plasma modified kapok fiber optimum.

More and more concern for environmental problems has led public to use natural and environmentally benign sound-absorbing materials. In this study, the sound-absorbing nonwoven composites based on kapok fiber and hollow polyester fiber were developed and sound absorption properties of kapok fiber nonwoven composites were investigated in the low frequency region of 100-500 Hz using the impedance tube method. The poor sound-absorbing at low-frequency is one of the difficult problems that urgently need to be solved in fibrous sound-absorbing materials. The effects of physical parameters, including bulk density and thickness, and depth of back cavity on sound absorption properties of composites were studied. Increasing of the bulk density, thickness and depth of back cavity is contribute to improve sound absorption properties of composites at low frequency. The comparisons of kapok fiber with polypropylene (PP) fiber and hollow polyester fiber indicated that as a natural fiber, kapok fiber had a superior acoustical properties at low frequency.

Modified kapok fiber (MKF) was prepared by reacting with succinic anhydride after microwave pretreatment. The preparing conditions (microwave power and pretreatment time) were optimized in this study. And the effects of MKF dosage, PH and contact time on the removal of Hg (II) ion from aqueous solution was studied, the results indicated that when the initial Hg (II) ion concentration was 100mg/L, the adsorption capacity of MKF was high effective with the MKF dose was 5g/L , PH was 4.0 and the contact time was 2h,the equilibrium adsorption capacity of MKF was 19.21 mg/g and the removal rate of Hg (II) ion was 97.13%. All the results indicated that the MKF was a effective adsorbent for removal of Hg (II) ion.

Kapok fiber is getting more and more extensive attention in research and application because of its excellent natural characteristics such as its lightness, super warmth, anti-bacterial, anti-mite etc. in recent years. On the other hand, the features of short fiber length, low breaking elongation, water repellency and oil absorptive in surface, make it difficult when spinning and dyeing, and hinder its application and popularization in the field of textiles. This paper discusses the fiber structure, physical and chemical properties, spinning and dyeing process performance of kapok fiber, points out that it is up to 80% ~ 90% fiber hollowness, so very lower fiber apparent density as only 0.29g/cm3, water repellency, anti-bacterial, anti-mite, have potentially wide application. However its spinning and dyeing performance is poor, the process cost is higher and the yarn quality needs to be improved. In this paper, the main types of kapok fiber products and the reason that restricting the fiber development and application to consumption market are analyzed. Finally, the paper puts forward the countermeasures concerning the further utilization with kapok fiber characteristics, and further expanding the development as a new generation of green ecological kapok textiles in the future.