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  1. Eco-friendly bio-based adhesive for plywood from natural rubber latex (NRL)-blended isocyanate cross-linked starch
    Soubam T, Gupta A, Jamari SS
    Environ Sci Pollut Res Int, 2023 Dec;30(60):124610-124618.
    PMID: 35610450 DOI: 10.1007/s11356-022-20788-9
    Synthetic adhesives used in the production of plywood are a matter of concern because of the emission of carcinogenic gas formaldehyde, increased environmental pollution, and the depletion of fossil fuels. In this study, a bioadhesive composed of natural rubber latex (NRL) and rice starch was developed. However, rice starch has low moisture resistance, resulting in low adhesion. Thus, to enhance the effectiveness of NRL-blended rice starch-based bioadhesive, rice starch was cross-linked with polymeric 4,4″-diphenylmethane diisocyanate (pMDI) resin, which is an environment-friendly, formaldehyde free, and moisture resistant that is highly compatible with starch. The chemical interaction, viscosity, solid content, and gel time of the developed NRL-isocyanate cross-linked rice starch-based bioadhesive was investigated. The efficacy of the formulated bioadhesive was demonstrated by the fabrication of plywood. The presence of isocyanate and urethane capabilities in the bioadhesive formulations was confirmed by Fourier transform infrared spectroscopy (FTIR). The bioadhesive type Iso-A was discovered to have the highest viscosity of 8270 mPa.s, whereas Iso-B has the shortest gel time of 3.46 min and the highest solid content of 44%; the higher solid content accelerates the gel time. In terms of physical and mechanical properties of plywood, Iso-B has the lowest thickness swelling (TS) value of 13%, lowest water absorption (WA) value of 52% and shear strength value of 1.92 MPa, which corresponds to the ISO 12466-2-2007 standard requirements. Based on the results, NRL-blended isocyanate starch-based bioadhesive could be a good potential raw material for eco-friendly plywood industries with adequate accuracy.
    Matched MeSH terms: Adhesives/chemistry
  2. Development and characterization novel bio-adhesive for wood using kenaf core (Hibiscus cannabinus) lignin and glyoxal
    Hazwan Hussin M, Aziz AA, Iqbal A, Ibrahim MNM, Latif NHA
    Int J Biol Macromol, 2019 Feb 01;122:713-722.
    PMID: 30399384 DOI: 10.1016/j.ijbiomac.2018.11.009
    The recent study focused on lignin-phenol-glyoxal (LPG) as an alternative way to replace toxic formaldehyde used in commercially available wood adhesives. The concern of the uses of carcinogenic formaldehyde in wood adhesive industry has become major problem over human health, environmental and economy issues. In this study, lignin isolated from Kenaf (Hibiscus cannabinus) via soda and Kraft pulping were modified into SLPG (soda lignin-phenol-glyoxal) and KLPG (Kraft lignin-phenol-glyoxal) adhesives and were compared to phenol-formaldehyde (PF). Complementary analyses such as Fourier Transform Infrared (FTIR) spectroscopy, 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy, thermal stability; Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were utilized to characterize all isolated lignin samples. The physical properties of the resins were further characterized in term of viscosity, gel time and total solid content. It was found that soda lignin comprised higher phenolic OH content and greater molecular weight compared to Kraft lignin. Various molar ratio of adhesives were applied on plywood and were mechanically tested. The 30% (w/w) SLPG has shown to have higher tensile strength and internal bonding stress at 72.08 MPa and 53.83 N mm-2 respectively to that of PF.
    Matched MeSH terms: Adhesives/chemistry*
  3. Fulltext Characterization of modified tapioca starch solutions and their sprays for high temperature coating applications
    Naz MY, Sulaiman SA, Ariwahjoedi B, Shaari KZ
    ScientificWorldJournal, 2014;2014:375206.
    PMID: 24592165 DOI: 10.1155/2014/375206
    The objective of the research was to understand and improve the unusual physical and atomization properties of the complexes/adhesives derived from the tapioca starch by addition of borate and urea. The characterization of physical properties of the synthesized adhesives was carried out by determining the effect of temperature, shear rate, and mass concentration of thickener/stabilizer on the complex viscosity, density, and surface tension. In later stage, phenomenological analyses of spray jet breakup of heated complexes were performed in still air. Using a high speed digital camera, the jet breakup dynamics were visualized as a function of the system input parameters. The further analysis of the grabbed images confirmed the strong influence of the input processing parameters on full cone spray patternation. It was also predicted that the heated starch adhesive solutions generate a dispersed spray pattern by utilizing the partial evaporation of the spraying medium. Below 40°C of heating temperature, the radial spray cone width and angle did not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The discharge coefficient, mean flow rate, and mean flow velocity were significantly influenced by the load pressure but less affected by the temperature.
    Matched MeSH terms: Adhesives/chemistry
  4. Fulltext Effects of using pozzolan and Portland cement in the treatment of dispersive clay
    Vakili AH, Selamat MR, Moayedi H
    ScientificWorldJournal, 2013;2013:547615.
    PMID: 23864828 DOI: 10.1155/2013/547615
    Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable of reducing dispersion potential to almost zero percent in only 7 days; and a 2% cement content was capable of achieving similar result in 14 days. However, treatment by cement alone is costly and could jeopardize the long term performance. Thus, a combined 5% pozzolan and 1.5% cement content was found capable of reducing dispersion potential from 100% to zero percent in 14 days. The results indicate that although simultaneous treatment with pozzolan and cement would extend the required curing time in comparison to treatment by cement alone of a higher content, the task could still be carried out in a reasonable period of curing time while avoiding the drawbacks of using either pozzolan or cement alone.
    Matched MeSH terms: Adhesives/chemistry*
  5. Reinforced lignin-phenol-glyoxal (LPG) wood adhesives from coconut husk
    Aziz NA, Latip AFA, Peng LC, Latif NHA, Brosse N, Hashim R, et al.
    Int J Biol Macromol, 2019 Dec 01;141:185-196.
    PMID: 31479667 DOI: 10.1016/j.ijbiomac.2019.08.255
    Lignin was extracted from coconut husk via alkaline pulping, either Kraft or soda. The isolated lignin samples were classified as hydroxy-benzaldehyde, vanillin, and syringaldehyde type according to Fourier-transform Infrared Spectroscopy, 1H and 13C Nuclear Magnetic Resonance (NMR) spectra. Soda lignin (SL) showed higher thermal stability and glass transition temperature (Tg) than Kraft lignin (KL) as proven by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The soda-lignin-phenol-glyoxal (SLPG) resins with the optimum percentage of lignin substitution at 30% showed improved solid content and gel time in comparison to 30% of Kraft-lignin-phenol-glyoxal (KLPG) and phenol-glyoxal (PG) resin. The good mechanical properties in SLPG is due to the higher amount of molecular weight as well as higher phenolic and G-type unit in lignin that improve the properties of 30% SLPG adhesive. Moreover, the addition of layered double hydroxides (LDH) as reinforced filler up to 15%-30% SLPG adhesive blend shows a great performance (especially mechanical properties) as compared to 30% SLPG adhesive alone.
    Matched MeSH terms: Adhesives/chemistry*
  6. Production of oil palm (Elaeis guineensis) fronds lignin-derived non-toxic aldehyde for eco-friendly wood adhesive
    Hazwan Hussin M, Samad NA, Latif NHA, Rozuli NA, Yusoff SB, Gambier F, et al.
    Int J Biol Macromol, 2018 Jul 01;113:1266-1272.
    PMID: 29548919 DOI: 10.1016/j.ijbiomac.2018.03.048
    Lignocellulosic materials can significantly contribute to the development of eco-friendly wood adhesives. In this work, glyoxal-phenolic resins for plywood were prepared using organosolv lignin, which was isolated from black liquor recovered from organosolv pulping of oil palm fronds (OPF) and considered to be an alternative to phenol. Glyoxal, which is a dialdehyde obtained from several natural resources, was used as substitute for formaldehyde. The structure of organosolv lignin and the resins were characterized by FTIR and NMR, and for thermal stability by TGA and DSC. The resins were further studied for their viscosity, pH, solids content and gel times. The resins performance as wood adhesive was further established from mechanical test in terms of tensile strength and modulus of elasticity (MOE) to obtain the optimum ratios of organosolv lignin, which replaces phenol in organosolv lignin phenol glyoxal (OLPG) resins. The adhesive composition having 50% (w/w) of phenol substituted by organosolv lignin, termed as 50% OLPG showed highest adhesive strength compared to phenol formaldehyde (PF) commercial adhesive.
    Matched MeSH terms: Adhesives/chemistry*
  7. Liquefaction of kenaf (Hibiscus cannabinus L.) core for wood laminating adhesive
    Juhaida MF, Paridah MT, Mohd Hilmi M, Sarani Z, Jalaluddin H, Mohamad Zaki AR
    Bioresour Technol, 2010 Feb;101(4):1355-60.
    PMID: 19833509 DOI: 10.1016/j.biortech.2009.09.048
    A study was carried out to produce polyurethane (PU) as a wood laminating adhesive from liquefied kenaf core (LKC) polyols by reacting it with toluene-2,4-diisocyanate (TDI) and 1,4-butanediol (BDO). The LKC polyurethane (LKCPU) adhesive has a molecular weight (MW) of 2666, viscosity of 5370 mPa s, and solids content of 86.9%. The average shear strength of the rubberwood (RW) bonded with LKCPU adhesive was 2.9 MPa. Most of the sheared specimens experienced a total adhesive failure. The formation of air bubbles through the liberation of carbon dioxide was observed to reduce the adhesive penetration and bonding strength which was obviously seen on the sheared specimens. The percentage of catalyst used can be varied based on the usage and working time needed. Nonetheless, the physical properties of LKCPU produced in this work had shown good potential as edge-bonding adhesive.
    Matched MeSH terms: Adhesives/chemistry*
  8. Dynamic Interfacial Adhesion through Cucurbit[n]uril Molecular Recognition
    Liu J, Tan CSY, Scherman OA
    Angew Chem Int Ed Engl, 2018 07 16;57(29):8854-8858.
    PMID: 29663607 DOI: 10.1002/anie.201800775
    Supramolecular building blocks, such as cucurbit[n]uril (CB[n])-based host-guest complexes, have been extensively studied at the nano- and microscale as adhesion promoters. Herein, we exploit a new class of CB[n]-threaded highly branched polyrotaxanes (HBP-CB[n]) as aqueous adhesives to macroscopically bond two wet surfaces, including biological tissue, through the formation of CB[8] heteroternary complexes. The dynamic nature of these complexes gives rise to adhesion with remarkable toughness, displaying recovery and reversible adhesion upon mechanical failure at the interface. Incorporation of functional guests, such as azobenzene moieties, allows for stimuli-activated on-demand adhesion/de-adhesion. Macroscopic interfacial adhesion through dynamic host-guest molecular recognition represents an innovative strategy for designing the next generation of functional interfaces, biomedical devices, tissue adhesives, and wound dressings.
    Matched MeSH terms: Tissue Adhesives/chemistry*
  9. Mucoadhesive chitosan-coated nanostructured lipid carriers for oral delivery of amphotericin B
    Ling Tan JS, Roberts CJ, Billa N
    Pharm Dev Technol, 2019 Apr;24(4):504-512.
    PMID: 30132723 DOI: 10.1080/10837450.2018.1515225
    This study describes the properties of an amphotericin B-containing mucoadhesive nanostructured lipid carrier (NLC), with the intent to maximize uptake within the gastrointestinal tract. We have reported previously that lipid nanoparticles can significantly improve the oral bioavailability of amphotericin B (AmpB). On the other hand, the aggregation state of AmpB within the NLC has been ascribed to some of the side effects resulting from IV administration. In the undissolved state, AmpB (UAmpB) exhibited the safer monomeric conformation in contrast to AmpB in the dissolved state (DAmpB), which was aggregated. Chitosan-coated NLC (ChiAmpB NLC) presented a slightly slower AmpB release profile as compared to the uncoated formulation, achieving 26.1% release in 5 hours. Furthermore, the ChiAmpB NLC formulation appeared to prevent the expulsion of AmpB upon exposure to simulated gastrointestinal pH media, whereby up to 63.9% of AmpB was retained in the NLC compared to 56.1% in the uncoated formulation. The ChiAmpB NLC demonstrated mucoadhesive properties in pH 5.8 and 6.8. Thus, the ChiAmpB NLC formulation is well-primed for pharmacokinetic studies to investigate whether delayed gastrointestinal transit may be exploited to improve the systemic bioavailability of AmpB, whilst simultaneously addressing the side-effect concerns of AmpB.
    Matched MeSH terms: Adhesives/chemistry*
  10. Fulltext First evidence for temporary and permanent adhesive systems in the stalked barnacle cyprid, Octolasmis angulata
    Yap FC, Wong WL, Maule AG, Brennan GP, Chong VC, Lim LH
    Sci Rep, 2017 Mar 22;7:44980.
    PMID: 28327603 DOI: 10.1038/srep44980
    Although there have been extensive studies on the larval adhesion of acorn barnacles over the past few decades, little is known about stalked barnacles. For the first time, we describe the larval adhesive systems in the stalked barnacle, Octolasmis angulata and the findings differ from previous reports of the temporary (antennulary) and cement glands in thoracican barnacles. We have found that the temporary adhesives of cyprid are produced by the clustered temporary adhesive glands located within the mantle, instead of the specialised hypodermal glands in the second antennular segment as reported in the acorn barnacles. The temporary adhesive secretory vesicles (TASV) are released from the gland cells into the antennule via the neck extensions of the glands, and surrounded with microtubules in the attachment disc. Cement glands undergo a morphological transition as the cyprid grows. Synthesis of the permanent adhesives only occurs during the early cyprid stage, and is terminated once the cement glands reach maximum size. Evidence of the epithelial invaginations on the cement glands supports the involvement of exocytosis in the secretion of the permanent adhesives. This study provides new insight into the larval adhesives system of thoracican barnacles.
    Matched MeSH terms: Adhesives/chemistry*
  11. Polylactic-co-glycolic acid mesh coated with fibrin or collagen and biological adhesive substance as a prefabricated, degradable, biocompatible, and functional scaffold for regeneration of the urinary bladder wall
    Salem SA, Hwei NM, Bin Saim A, Ho CC, Sagap I, Singh R, et al.
    J Biomed Mater Res A, 2013 Aug;101(8):2237-47.
    PMID: 23349110 DOI: 10.1002/jbm.a.34518
    The chief obstacle for reconstructing the bladder is the absence of a biomaterial, either permanent or biodegradable, that will function as a suitable scaffold for the natural process of regeneration. In this study, polylactic-co-glycolic acid (PLGA) plus collagen or fibrin was evaluated for its suitability as a scaffold for urinary bladder construct. Human adipose-derived stem cells (HADSCs) were cultured, followed by incubation in smooth muscle cells differentiation media. Differentiated HADSCs were then seeded onto PLGA mesh supported with collagen or fibrin. Evaluation of cell-seeded PLGA composite immersed in culture medium was performed under a light and scanning microscope. To determine if the composite is compatible with the urodynamic properties of urinary bladder, porosity and leaking test was performed. The PLGA samples were subjected to tensile testing was pulled until PLGA fibers break. The results showed that the PLGA composite is biocompatible to differentiated HADSCs. PLGA-collagen mesh appeared to be optimal as a cell carrier while the three-layered PLGA-fibrin composite is better in relation to its leaking/ porosity property. A biomechanical test was also performed for three-layered PLGA with biological adhesive and three-layered PLGA alone. The tensile stress at failure was 30.82 ± 3.80 (MPa) and 34.36 ± 2.57 (MPa), respectively. Maximum tensile strain at failure was 19.42 ± 2.24 (mm) and 23.06 ± 2.47 (mm), respectively. Young's modulus was 0.035 ± 0.0083 and 0.043 ± 0.012, respectively. The maximum load at break was 58.55 ± 7.90 (N) and 65.29 ± 4.89 (N), respectively. In conclusion, PLGA-Fibrin fulfils the criteria as a scaffold for urinary bladder reconstruction.
    Matched MeSH terms: Tissue Adhesives/chemistry
  12. Fulltext Enhanced gastrointestinal survivability of recombinant Lactococcus lactis using a double coated mucoadhesive film approach
    Tan EW, Tan KY, Phang LV, Kumar PV, In LLA
    PLoS One, 2019;14(7):e0219912.
    PMID: 31335895 DOI: 10.1371/journal.pone.0219912
    Vaccine administration via the oral route is preferable to parenteral routes due to ease of administration. To date, most available oral vaccines comprises of live attenuated pathogens as oppose to peptide-based vaccines due to its low bioavailability within the gastrointestinal (GI) tract. Over the years, probiotic-based peptide delivery vehicles comprising of lactic acid bacteria such as Lactococcus lactis has emerged as an interesting alternative due to its generally recognized as safe (GRAS) status, a fully sequenced genome, transient gut colonization time, and is an efficient cellular factory for heterologous protein production. However, its survivability through the GI tract is low, thus better delivery approaches are being explored to improve its bioavailability. In this study, we employ the incorporation of a double coated mucoadhesive film consisting of sodium alginate and Lycoat RS 720 film as the inner coat. The formulated film exhibits good mechanical properties of tensile strength and percent elongation for manipulation and handling with an entrapment yield of 93.14±2.74%. The formulated mucoadhesive film is subsequently loaded into gelatin capsules with an outer enteric Eudragit L100-55 coating capable of a pH-dependent breakdown above pH 5.5 to protect against gastric digestion. The final product and unprotected controls were subjected to in vitro simulated gastrointestinal digestions to assess its survivability. The product demonstrated enhanced protection with an increase of 69.22±0.67% (gastric) and 40.61±8.23% (intestinal) survivability compared to unprotected controls after 6 hours of sequential digestion. This translates to a 3.5 fold increase in overall survivability. Owing to this, the proposed oral delivery system has shown promising potential as a live gastrointestinal vaccine delivery host. Further studies involving in vivo gastrointestinal survivability and mice immunization tests are currently being carried out to assess the efficacy of this novel oral delivery system in comparison to parenteral routes.
    Matched MeSH terms: Adhesives/chemistry
  13. Biocompatible and mucoadhesive bacterial cellulose-g-poly(acrylic acid) hydrogels for oral protein delivery
    Ahmad N, Amin MC, Mahali SM, Ismail I, Chuang VT
    Mol Pharm, 2014 Nov 3;11(11):4130-42.
    PMID: 25252107 DOI: 10.1021/mp5003015
    Stimuli-responsive bacterial cellulose-g-poly(acrylic acid) hydrogels were investigated for their potential use as an oral delivery system for proteins. These hydrogels were synthesized using electron beam irradiation without any cross-linking agents, thereby eliminating any potential toxic effects associated with cross-linkers. Bovine serum albumin (BSA), a model protein drug, was loaded into the hydrogels, and the release profile in simulated gastrointestinal fluids was investigated. Cumulative release of less than 10% in simulated gastric fluid (SGF) demonstrated the potential of these hydrogels to protect BSA from the acidic environment of the stomach. Subsequent conformational stability analyses of released BSA by SDS-PAGE, circular dichroism, and an esterase activity assay indicated that the structural integrity and bioactivity of BSA was maintained and preserved by the hydrogels. Furthermore, an increase in BSA penetration across intestinal mucosa tissue was observed in an ex vivo penetration experiment. Our fabricated hydrogels exhibited excellent cytocompatibility and showed no sign of toxicity, indicating the safety of these hydrogels for in vivo applications.
    Matched MeSH terms: Adhesives/chemistry
  14. Properties of the tray adhesive of an addition polymerizing silicone to impression tray materials
    Sulong MZ, Setchell DJ
    J Prosthet Dent, 1991 Dec;66(6):743-7.
    PMID: 1805022
    Adhesive bond strength studies for the tray adhesive of an addition vinyl polysiloxane (President) impression material were conducted with an acrylic resin, chromium-plated brass, and plastic trays. Tensile and shear stress studies were performed on the Instron Universal testing machine. Acrylic resin specimens roughened with 80-grit silicon carbide paper exhibited appreciably higher bond strengths compared with different types of tray material and methods of surface preparation.
    Matched MeSH terms: Adhesives/chemistry*
  15. Mucoadhesive Low Molecular Chitosan Complexes to Protect rHuKGF from Proteolysis: In-vitro Characterization and FHs 74 Int Cell Proliferation Studies
    Tee YN, Kumar PV, Maki MAA, Elumalai M, Rahman SAKMEH, Cheah SC
    Curr Pharm Biotechnol, 2021;22(7):969-982.
    PMID: 33342408 DOI: 10.2174/1389201021666201218124450
    BACKGROUND: Recombinant Keratinocyte Growth Factor (rHuKGF) is a therapeutic protein used widely in oral mucositis after chemotherapy in various cancers, stimulating lung morphogenesis and gastrointestinal tract cell proliferation. In this research study, chitosan-rHuKGF polymeric complex was implemented to improve the stability of rHuKGF and used as rejuvenation therapy for the treatment of oral mucositis in cancer patients.

    OBJECTIVE: Complexation of rHuKGF with mucoadhesive low molecular weight chitosan to protect rHuKGF from proteolysis and investigate the effect of chitosan-rHuKGF complex on the proliferation rate of FHs 74 Int cells.

    METHODS: The interaction between chitosan and rHuKGF was studied by molecular docking. Malvern ZetaSizer Nano Zs and Fourier-Transform Infrared spectroscopy (FTIR) tests were carried out to characterize the chitosan-rHuKGF complex. In addition, SDS-PAGE was performed to investigate the interaction between chitosan-rHuKGF complex and pepsin. The effect of chitosan-rHuKGF complex on the proliferation rate of FHs 74 Int cells was studied by MTT assay.

    RESULTS: Chitosan-rHuKGF complex was formed through the hydrogen bonding proven by the docking studies. A stable chitosan-rHuKGF complex was formed at pH 4.5 and was protected from proteolysis and assessed by SDS PAGE. According to the MTT assay results, chitosan-rHuKGF complex increased the cell proliferation rate of FHs 74 Int cells.

    CONCLUSION: The developed complex improved the stability and the biological function of rHuKGF.

    Matched MeSH terms: Adhesives/chemistry*
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