91 results on '"Zuber, Mohammad"'
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2. Effect of vascular geometry on haemodynamic changes in a carotid artery bifurcation using numerical simulation
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Abhilash, H.N., Yanagita, Yoshiki, Pai, Raghuvir, Zuber, Mohammad, Tamagawa, Masaaki, K, Prakashini, Kamath S, Ganesh, R, Padmakumar, Barboza, A.B.V., Rao, V.R.K., and Khader, S.M. Abdul
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- 2024
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3. Nasal airflow comparison in neonates, infant and adult nasal cavities using computational fluid dynamics
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Corda, John Valerian, Shenoy, B Satish, Ahmad, Kamarul Arifin, Lewis, Leslie, K, Prakashini, Khader, S. M. Abdul, and Zuber, Mohammad
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- 2022
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4. Computational flow analysis of a single peristaltic wave propagation in the ureter
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Keni, Laxmikant G., Hayoz, Mattias Jan, Khader, Shah Mohammad Abdul, Hegde, Padmaraj, Prakashini, K., Tamagawa, Masaaki, Satish Shenoy, B., Hameed, B.M. Zeeshan, and Zuber, Mohammad
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- 2021
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5. Finite element analysis of hip implant with varying in taper neck lengths under static loading conditions
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Chethan, K.N., Shyamasunder Bhat, N., Zuber, Mohammad, and Satish Shenoy, B
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- 2021
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6. Molecular engineering and morphology of polyurethane elastomers containing various molecular weight of macrodiol
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Naheed, Shazia, Zuber, Mohammad, Barikani, Mehdi, and Salman, Mahwish
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- 2021
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7. Wear estimation of trapezoidal and circular shaped hip implants along with varying taper trunnion radiuses using finite element method
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K N, Chethan, Ogulcan, Guldeniz, Bhat N, Shyamasunder, Zuber, Mohammad, and Shenoy B, Satish
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- 2020
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8. Finite element analysis of immature teeth filled with MTA, Biodentine and Bioaggregate
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Eram, Afiya, Zuber, Mohammad, Keni, Laxmikant G, Kalburgi, Sagar, Naik, Rajaram, Bhandary, Shruti, Amin, Swathi, and Badruddin, Irfan Anjum
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- 2020
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9. Dyeing of UV irradiated cotton and polyester fabrics with multifunctional reactive and disperse dyes
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Bhatti, Ijaz Ahmad, Adeel, Shahid, Parveen, Sajida, and Zuber, Mohammad
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- 2016
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10. Bio-based polyurethane: An efficient and environment friendly coating systems: A review
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Noreen, Aqdas, Zia, Khalid Mahmood, Zuber, Mohammad, Tabasum, Shazia, and Zahoor, Ameer Fawad
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- 2016
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11. Surface characteristics of chitin-based shape memory polyurethane elastomers
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Zia, Khalid Mahmood, Zuber, Mohammad, Barikani, Mehdi, Bhatti, Ijaz Ahmad, and Khan, Mohammad Bilal
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- 2009
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12. Surface characteristics of UV-irradiated polyurethane elastomers extended with α, ω-alkane diols
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Zia, Khalid Mahmood, Bhatti, Ijaz Ahmad, Barikani, Mehdi, Zuber, Mohammad, and Islam-ud-Din
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- 2008
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13. Preparation and characterization of guar gum based polyurethanes.
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Anjum, Anbreen, Zuber, Mohammad, Zia, Khalid Mahmood, Anjum, Muhammad Naveed, and Aftab, Waseem
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GUAR gum , *POLYURETHANES , *PREPOLYMERS , *DIFFERENTIAL scanning calorimetry , *BINDING agents - Abstract
Guar gum (plant-based polysaccharide) is a promising candidate with immense potential. It is used as emulsifier, thickener, stabilizer, and as binding agent in many industries. In the present project, it was planned to synthesize guar gum based polyurethanes by varying the amount of guar gum. Guar gum (GG) was used along with hydroxyl-terminated polybutadiene (HTPB) as soft segment, which was then reacted with isophorone diisocyanate (IPDI) to form PU pre-polymers. In last step, these –NCO terminated pre-polymers were extended with 1,4 butane diol as chain extender. The prepared polyurethane samples were then characterized by using FTIR , solid-state 1HNMR and X-ray diffraction (XRD). Thermal behavior of the samples was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Results indicated that the incorporation of guar gum in PU backbone improved its thermal behavior and crystallinity. • Guar gum is a plant-based polysaccharide, promising candidates with immense potential. • Synthesis of guar gum based polyurethanes • The structure and morphology of the material was studied by FTIR , solid-state static 1HNMR, XRD. • Thermal behavior of the prepared PU samples was checked by TGA and DSC analysis. • Incorporation of guar gum in PU backbone improved its thermal behavior and crystallinity. [ABSTRACT FROM AUTHOR]
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- 2021
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14. Influence of ultrasonic radiation on extraction and green dyeing of mordanted cotton using neem bark extract.
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Zia, Khalid Mahmood, Adeel, Shahid, Rehman, Fazal-ur-, Aslam, Habiba, Khosa, Muhammad Kaleem, and Zuber, Mohammad
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ULTRASONIC waves ,NEEM ,COTTON textiles ,BARK ,DYES & dyeing ,COTTON - Abstract
The current research presents the exploration of coloring potential of neem bark under the influence of ultrasonic treatment. It is found that good color strength is obtained when tannin from bark is extracted in acidified methanol medium and is used to dye irradiated cotton fabric. New shades and good ratings of fastness were obtained when optimal fabric was mordanted with herbal biomolecules where excellent rating has been obtained after bio-mordanting the fabrics under optimal conditions. It is concluded that US treatment being green tool in natural dyeing has a great potential to isolate colorants from plant sources under mild conditions. [ABSTRACT FROM AUTHOR]
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- 2019
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15. Synthesis and characterization of chitosan-based waterborne polyurethane for textile finishes.
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Naz, Farah, Zuber, Mohammad, Mehmood Zia, Khalid, Salman, Mahwish, Chakraborty, Jeet, Nath, Ipsita, and Verpoort, Francis
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CHITOSAN , *POLYURETHANES , *TEXTILE finishing , *ORGANIC synthesis , *BIOMEDICAL materials - Abstract
Graphical abstract Highlights • A series of chitosan-based waterborne polyurethane (CS-WPU) emulsions were synthesized. • The chain extension step was done by using different mole ratios of chitosan. • The CS-WPU emulsion was applied on plain weave poly-cotton dyed and printed fabrics by using pad-dry-cure techniques. • Incorporation of chitosan affects the tear strength and antimicrobial activity of poly-cotton dyed and printed fabrics. Abstract Chitosan has gained an increased interest of researchers due to its nontoxic, biodegradable, biocompatible and renewable properties as well as its antimicrobial activity. In this work, a series of chitosan-based waterborne polyurethane (CS-WPU) emulsions were synthesized. The synthesis was accomplished by using a two-step emulsion polymerization process. The pre-polymer was prepared using hexamethylene diisocyanate (HDI) and polyethylene glycol (PEG; MW = 6 kDa). Afterwards, the chain extension step was performed by using different mole ratios of chitosan. Moreover, the effect of chitosan on physicochemical properties of the emulsion was studied. To evaluate textile performances such as tear strength, tensile strength and pilling, the CS-WPU emulsion was applied on different plain weave polyester cotton dyed and printed fabrics by using pad-dry cure techniques. The antimicrobial activity of the treated and untreated fabrics was also evaluated via the agar diffusion method. The results displayed that incorporation of chitosan has prominent effects on tensile tear strength, tear strength and antimicrobial activity of polyester cotton dyed and printed fabrics. Moreover, antimicrobial activity was considerably enhanced as the mole ratio of the chitosan was increased. The results emphasize that CS-WPU based on HDI exhibits a better performance as compared to IPDI. [ABSTRACT FROM AUTHOR]
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- 2018
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16. Microbial production of polyhydroxyalkanoates (PHAs) and its copolymers: A review of recent advancements.
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Anjum, Anbreen, Zuber, Mohammad, Zia, Khalid Mahmood, Noreen, Aqdas, Anjum, Muhammad Naveed, and Tabasum, Shazia
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POLYHYDROXYALKANOATES , *COPOLYMERS , *MICROORGANISMS , *MINERAL oils , *QUALITY of life , *WASTE management - Abstract
Traditional mineral oil based plastics are important commodity to enhance the comfort and quality of life but the accumulation of these plastics in the environment has become a major universal problem due to their low biodegradation. Solution to the plastic waste management includes incineration, recycling and landfill disposal methods. These processes are very time consuming and expensive. Biopolymers are important alternatives to the petroleum-based plastics due to environment friendly manufacturing processes, biodegradability and biocompatibility. Therefore use of novel biopolymers, such as polylactide, polysaccharides, aliphatic polyesters and polyhydroxyalkanoates is of interest. PHAs are biodegradable polyesters of hydroxyalkanoates (HA) produced from renewable resources by using microorganisms as intracellular carbon and energy storage compounds. Even though PHAs are promising candidate for biodegradable polymers, however, the production cost limit their application on an industrial scale. This article provides an overview of various substrates, microorganisms for the economical production of PHAs and its copolymers. Recent advances in PHAs to reduce the cost and to improve the performance of PHAs have also been discussed. [ABSTRACT FROM AUTHOR]
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- 2016
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17. Collagen based polyurethanes—A review of recent advances and perspective.
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Zuber, Mohammad, Zia, Fatima, Zia, Khalid Mahmood, Tabasum, Shazia, Salman, Mahwish, and Sultan, Neelam
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COLLAGEN , *POLYURETHANES , *LIGAMENT physiology , *TENSILE strength , *BIOMIMETIC materials , *VITAMIN C deficiency - Abstract
Collagen is mostly found in fibrous tissues such as tendons, ligaments and skin. Collagen makes up approximately 30% of the proteins within the body. These are tough and strong structures found all over the body: in bones, tendons and ligaments. Collagen being the most abundant protein provides tensile strength via cell matrix interactions to tissue architecture. Biomimetic materials of collagen origin gained wide spread acceptance in clinical applications. Vitamin C deficiency causes scurvy a serious and painful disease in which defective collagen prevents the formation of strong connective tissue, gums deteriorate and bleed, with loss of teeth; skin discolors, and wounds do not heal. Effective collagens prevent the manifestation of such disorders. Polyurethanes on the other hand are frequently used for various applications as they offered in wide-ranging of compositions, properties and complex structures. Collagen/PU bio-composites have potential array for biomedical applications. Considering versatile properties of the elongated fibrils and wide industrial and biomedical applications including biocompatibility of polyurethane, this review shed a light on collagen based polyurethane materials with their potential applications especially focusing the bio-medical field. [ABSTRACT FROM AUTHOR]
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- 2015
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18. Classification of actuation mechanism designs with structural block diagrams for flapping-wing drones: A comprehensive review.
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Singh, Spoorthi, Zuber, Mohammad, Hamidon, Mohd Nizar, Mazlan, Norkhairunnisa, Basri, Adi Azriff, and Ahmad, Kamarul Arifin
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BATS , *HUMMINGBIRDS , *BLOCK diagrams , *BLOCK designs , *STRUCTURAL design , *MICRO air vehicles , *BIOMIMETIC materials , *JOB performance - Abstract
Flying insects are interesting dipteras with an outstanding wing structure that makes their flight efficient. It is challenging to mimic flying insects and create effective artificial flapping drones that can imitate their flying techniques. The smaller insect-size drones have remarkable applications, but they need lightweight and minimal connecting structures for their transmission mechanism. Many operating methods, such as the traditional rotary actuation method and non-conventional oscillatory mechanisms with multiple transmission configurations, are popularly adopted. The classification and recent design innovations with flapping actuation mechanism challenges, particularly bio-inspired (biomimetics) and bio-morphic types of flapping-wing aerial vehicles from micro to pico-scale, are discussed in this review paper. For ease of understanding, we have attempted to depict the actuation mechanisms in the form of block diagrams. The ability of hybrid efficient mechanisms to improve the flapping frequency of wings and flapping actuation design process, including other parameters, such as flapping angle, lift generation, and hovering ability with current driving mechanisms, is also discussed. Depending on their endearing resemblance, we have segregated Flapping-Wing Micro Air Vehicle (FWMAV) design patterns like birds, small birds, nano hummingbirds, moths, bats, biomorphic types, flapping test bench models, and fully flyable models, which are characterized by their flight modes. Important flapping actuation systems that can be used to achieve hovering capability are highlighted. The actuation mechanisms' specifications and configurations are expanded by focusing on the need of flapping frequency and stroke angle controllability via the linkage mechanisms with insight into flapping patterns. Besides that, the requirements for the sustainability of flying patterns during manual and automatic launches were investigated. In addition, the different researchers' annual progress on their Flapping-wing models has been emphasized. The best performing prototypes with their flapping actuation mechanism contributions to achieving better lift and long-duration flight sustainability are articulated through ranking. An insight into some of the significant challenges and future work on flapping performance levels are also discussed. [ABSTRACT FROM AUTHOR]
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- 2022
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19. Aerodynamic comparison of slotted and non-slotted diffuser casings for Diffuser Augmented Wind Turbines (DAWT).
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Sridhar, Surya, Zuber, Mohammad, B., Satish Shenoy, Kumar, Amit, Ng, Eddie Y.K., and Radhakrishnan, Jayakrishnan
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HORIZONTAL axis wind turbines , *WIND turbines , *VERTICAL axis wind turbines , *NOISE pollution , *WIND tunnel testing , *TORQUE , *DIFFUSERS (Fluid dynamics) - Abstract
The ability of Horizontal & Vertical Axis Wind Turbine (HAWT & VAWT) to harness the incoming wind is limited due to several factors such as structural constrains, fatigue problems, geographical and ecological issues, noise pollution, vibrational & acoustic losses. Diffuser Augmented Wind Turbine (DAWT) exploits the concepts of velocity augmentation to maximize power production efficiently when compared to conventional approach. The optimization of the geometric parameters can help the augmentation capability of the diffuser. This study investigates the aerodynamic effect of slits on diffuser casings and the performance of slotted and non-slotted diffuser casings is compared using 3D CFD analysis and validated experimentally. The performance of the studied diffusers is analysed in terms of velocity at the rotor plane, augmentation ratio, and swallowed mass flow rate. At tip speed corresponding to 62 m/s, the performance parameters of slotted DAWTs showed an increase by 27.4% and 46.8% compared to non-slotted DAWTs and open turbines, respectively. It is also observed that the inclusion of slotted and non-slotted diffusers enclosing the rotor resulted in an average augmentation of 2.01 and 1.36 in both power and torque produced, respectively. • DAWT have proven to overcome the Betz limit and reduce tip losses & noise. • Addition of slots to diffuser casing has shown to increase both torque and power. • Slotted DAWTs have shown to produce higher power with greater efficiency. [ABSTRACT FROM AUTHOR]
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- 2022
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20. Performance behavior of modified cellulosic fabrics using polyurethane acrylate copolymer.
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Zuber, Mohammad, Shah, Sayyed Asim Ali, Jamil, Tahir, and Asghar, Muhammad Irfan
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CELLULOSE fibers , *POLYURETHANES , *ACRYLATES , *COPOLYMERS , *EMULSIONS , *MOLECULAR weights - Abstract
Abstract: The surface of the cellulosic fabrics was modified using self-prepared emulsions of polyurethane acrylate copolymers (PUACs). PUACs were prepared by varying the molecular weight of polycaprolactone diol (PCL). The PCL was reacted with isophorone diisocyanate (IPDI) and chain was extended with 2-hydroxy ethyl acrylate (HEA) to form vinyl terminated polyurethane (VTPU) preploymer. The VTPU was further co-polymerized through free radical polymerization with butyl acrylate in different proportions. The FT-IR spectra of monomers, prepolymers and copolymers assured the formation of proposed PUACs structure. The various concentrations of prepared PUACs were applied onto the different fabric samples using dip-padding techniques. The results revealed that the application of polyurethane butyl acrylate copolymer showed a pronounced effect on the tear strength and pilling resistance of the treated fabrics. [Copyright &y& Elsevier]
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- 2014
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21. Chitin based polyurethanes using hydroxyl terminated polybutadiene, part III: Surface characteristics.
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Zia, Khalid Mahmood, Zuber, Mohammad, Saif, Muhammad Jawwad, Jawaid, Mohammad, Mahmood, Kashif, Shahid, Muhammad, Anjum, Muhammad Naveed, and Ahmad, Mirza Nadeem
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CHITIN , *POLYURETHANES , *HYDROXYL group , *POLYBUTADIENE , *SURFACE chemistry , *TOLUENE diisocyanate , *ANTIBACTERIAL agents , *DRUG activation - Abstract
Abstract: Hydroxy terminated polybutadiene (HTPB)-chitin based polyurethanes (PUs) with controlled hydrophobicity were synthesized using HTPB and toluene diisocyanate (TDI). The prepolymer was extended with different mass ratios of chitin and 1,4-butane diol (BDO). The effect of chitin contents in chain extender (CE) proportions on surface properties was studied and investigated. Incorporation of chitin contents into the final PU showed decrease in contact angle value of water drop, water absorption (%) and swelling behavior. The antibacterial activity of the prepared samples was affected by varying the chitin contents in the chemical composition of the final PU. The results demonstrated that the use of prepared material can be suggested as non-absorbable suture. [Copyright &y& Elsevier]
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- 2013
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22. Properties of the modified cellulosic fabrics using polyurethane acrylate copolymers
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Tabasum, Shazia, Zuber, Mohammad, Jabbar, Abdul, and Zia, Khalid Mahmood
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CELLULOSE , *POLYURETHANES , *ACRYLATES , *COPOLYMERS , *EMULSION polymerization , *CRYSTAL structure , *MOLECULAR weights - Abstract
Abstract: Polyurethane acrylate copolymers (PAC) were synthesized via emulsion polymerization following three step synthesis process using toluene-2,4-diisocyanate, hydroxy terminated poly(caprolactone) diol, 2-hydroxyethylacrylate (HEA) and butyl acrylate (BuA). Structural characteristics of the synthesized polyurethane acrylate copolymer (PAC) were studied using Fourier Transform Infrared (FT-IR) spectrophotometer and are with accordance with the proposed PAC structure. The physicochemical properties such as solid contents (%), tackiness, film appearance and emulsion stability were studied, discussed and co-related with other findings. The plain weave poly-cotton printed fabrics after application of PAC was evaluated applying colorfastness standard test method. The results revealed that emulsion stability is the main controlling factor of the synthesized material in order to get better applications and properties. The emulsion stability of the synthesized material increased with increase in molecular weight of the polycaprolactone diol. [Copyright &y& Elsevier]
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- 2013
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23. Antimicrobial and pilling evaluation of the modified cellulosic fabrics using polyurethane acrylate copolymers
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Tabasum, Shazia, Zuber, Mohammad, Jamil, Tahir, Shahid, Muhammad, and Hussain, Rizwan
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ANTI-infective agents , *PILLING (Textiles) , *POLYURETHANES , *CELLULOSE , *FOURIER transform infrared spectroscopy , *HYDROPHILIC compounds , *COPOLYMERS - Abstract
Abstract: Polyurethane acrylate copolymers (PACs) were synthesized by three step synthesis process via emulsion polymerization using toluene-2,4-diisocyanate, hydroxy terminated poly (caprolactone) diol (PCL), 2-hydroxyethylacrylate (HEA) and butyl acrylate (BuA). The proposed structure of the synthesized polyurethane acrylate copolymer (PAC) was confirmed using Fourier transform infrared (FTIR) spectrophotometer. The pilling characteristic and antimicrobial activities of the plain weave poly-cotton grey, white, printed and dyed fabric swatches after application of PAC were evaluated. The results revealed that by increasing the molecular weight of PCL in the synthesized PAC samples, the antimicrobial activities increased and this behavior was interpreted in term of increasing hydrophilic character. An increase in pilling ratings of the treated samples has been observed by increasing the molecular weight of the polycaprolactone diols in the synthesized PAC samples. [Copyright &y& Elsevier]
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- 2013
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24. Modification of cellulosic fibers by UV-irradiation. Part II: After treatments effects
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Zuber, Mohammad, Zia, Khalid Mahmood, Bhatti, Ijaz Ahmad, Ali, Zobia, Arshad, Muhammad Umair, and Saif, Muhammad Jawwad
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CELLULOSE , *ULTRAVIOLET radiation , *TREATMENT effectiveness , *COMPARATIVE studies , *ALKALINE solutions , *MOLECULAR weights - Abstract
Abstract: This work presents the comparative study on the dyeing behavior of cellulose fibers in alkaline solutions and under the influence of UV radiation. The cellulosic fabrics were pretreated followed by conventional mercerization technique or treatment with UV irradiation. For different time duration the reorganization of cellulose fibers by swelling treatments in alkaline solutions results in numerous structural modifications, causing changes of their accessibility and/or reactivity. The results revealed that the swelling of the cellulosic fibers depends on type of pre-treatment, dose of the radiation and the concentration of alkaline solution used. SEM analysis confirmed that UV irradiation of the cellulosic fibers leads to a higher swelling in comparison with any concentration of NaOH treatment. In comparison of both the treatments, the mercerized cellulosic fibers have shown better tear and tensile strength as compared to the untreated and UV irradiated one. There is adverse effect of UV radiation on the mechanical properties of UV radiation. Moreover, no loss in weight was observed after exposing the cellulose fabrics surface to UV radiation. [Copyright &y& Elsevier]
- Published
- 2012
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25. Modification of cellulosic fabric using polyvinyl alcohol, part-II: Colorfastness properties
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Zuber, Mohammad, Zia, Khalid Mahmood, Bhatti, Ijaz Ahmad, Jamil, Tahir, Fazal-ur-Rehman, and Rizwan, Ali
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CELLULOSE , *POLYVINYL alcohol , *COLORFASTNESS (Textiles) , *POLYESTER fibers , *FOURIER transform infrared spectroscopy , *CRYSTALLINE polymers - Abstract
Abstract: A series of aqueous solutions of poly(vinyl alcohol) of various commercial products were prepared and applied onto the surfaces of cotton and blends of cotton/polyester fabrics. Fourier transform infrared spectrophotometer was used to confirm the molecular structure of the polyvinyl alcohol used. Performance tests such as colorfastness to rubbing (dry and wet) and colorfastness to washing were determined. The controlling variables affecting the performance properties of the finished substrate such as post-treatment with poly(vinyl alcohol) of various commercial trades, concentration and dilutions were studied. Crocking, washing and hue change of the treated dyed and printed fabrics is accompanied by the formation of semi-inter-penetrated network structure due to the presence of the hydroxyl (–OH) groups which make feasible to a number of grafting and physical cross linking reactions of polymer backbone. [Copyright &y& Elsevier]
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- 2012
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26. Modification of cellulosic fabric using polyvinyl alcohol—Part-I: Physicochemical properties
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Zia, Khalid Mahmood, Zuber, Mohammad, Rizwan, Ali, Jamil, Tahir, Tabasum, Shazia, and Shahid, Muhammad
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CELLULOSE , *TEXTILES , *POLYVINYL alcohol , *POLYESTER fibers , *MOLECULAR structure , *INFRARED spectroscopy , *VISCOSITY - Abstract
Abstract: A series of poly(vinyl alcohol) of different commercial grades were prepared and applied onto the surfaces of cotton and blends of cotton/polyester fibers. The molecular structure was confirmed using Fourier Transform Infrared spectroscopy. Physicochemical properties such as viscosity and solid contents (%) were determined and discussed. Factors affecting the performance properties of the finished substrate such as post-treatment with poly(vinyl alcohol) of different grades, concentration and dilutions were studied. Fixation of the poly(vinyl alcohol) onto/or within the cellulose structure is accompanied by the formation of semi-inter-penetrated network structure thereby enhancing the association as well as providing very high stiffness. The results revealed that applications of poly(vinyl alcohol) on the textile fabrics in the finishing processes enables to enhance the stiffness as well as helps to improve its pilling resistance. [Copyright &y& Elsevier]
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- 2012
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27. Cytotoxicity and mechanical behavior of chitin–bentonite clay based polyurethane bio-nanocomposites
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Zia, Khalid Mahmood, Zuber, Mohammad, Barikani, Mehdi, Hussain, Rizwan, Jamil, Tahir, and Anjum, Sohail
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CELL-mediated cytotoxicity , *CHITIN , *BENTONITE , *CLAY , *POLYURETHANES , *NANOCOMPOSITE materials , *MONTMORILLONITE , *MECHANICAL behavior of materials - Abstract
Abstract: Chitin based polyurethane bio-nanocomposites (PUBNC) were prepared using chitin, Delite® HPS bentonite nanoclay enriched in montmorillonite (MMT), 4,4′-diphenylmethane diisocyanate (MDI) and polycaprolactone polyol CAPA 231 (3000g/mol−1). The prepolymers having different concentration of Delite HPS bentonite nanoclay were extended with 2moles of chitin. The structures of the resulted polymers were determined by FT-IR technique. The effect of nanoclay contents on mechanical properties and in vitro biocompatibility was investigated. The mechanical properties of the synthesized materials were improved with increase in the Delite HPS® bentonite nanoclay contents. Optimum mechanical properties were obtained from the PU bio-nanocomposite samples having 4% Delite HPS® bentonite nanoclay. The results revealed that the final PU bio-nanocomposite having 2% Delite HPS® bentonite nanoclay contents is ideal contenders for surgical threads with on going investigations into their in vitro biocompatibility, non-toxicity, and mechanical properties. [Copyright &y& Elsevier]
- Published
- 2011
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28. Preparation of rich handles soft cellulosic fabric using amino silicone based softener, part II: Colorfastness properties
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Zuber, Mohammad, Zia, Khalid Mahmood, Tabassum, Shazia, Jamil, Tahir, Barkaat-ul-Hasin, Syed, and Khosa, Muhammad Kaleem
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SILICONES , *COLORFASTNESS (Textiles) , *POLYESTER fibers , *COTTON textiles , *PILLING (Textiles) , *SURFACE area , *MIXING - Abstract
Abstract: The preparation of amino silicone based softeners with different emulsifiers was carried out and adsorbed onto the surfaces of cotton and blends of cotton/polyester fabrics. The softened fabrics have high surface area, so poorly performance in washing and rubbing fastness. It is obvious from the results of colorfastness to rubbing and washing that some of the samples of the dyed fabric treated with prepared softeners have shown some poor rating as compared to the untreated fabrics. However the other two samples have shown acceptable rubbing fastness results without losing softness and permanent handle. It can be observed that washing of the printed treated fabric remains unaffected almost in all the studied samples. Moreover, the application of the prepared softeners has imparted anti pilling property to the fabric. It can be seen that there is a remarkable increase in weights of treated fabrics as compared to the untreated fabrics. [Copyright &y& Elsevier]
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- 2011
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29. Synthesis of chitin–bentonite clay based polyurethane bio-nanocomposites
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Zuber, Mohammad, Zia, Khalid Mahmood, Mahboob, Shahid, Hassan, Muhammad, and Bhatti, Ijaz Ahmad
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CHITIN , *BENTONITE , *POLYURETHANES , *EMULSION polymerization , *MONTMORILLONITE , *MICROSCOPY , *NANOCOMPOSITE materials - Abstract
Abstract: Chitin based polyurethane bio-nanocomposites (PUBNC) were prepared by emulsion polymerization. A mixture of polymer and bentonite clay enriched in montmorillonite (MMT) was formed in emulsion polymerization, in which MMT dispersed differently depending on interaction of MMT with polymer chains. Cation exchange capacity (CEC) of bentonite clay enriched in montmorillonite was found 74meq/100g. The existence of the intercalated clay by PU in the hybrid was confirmed using optical microscope (OM) technique. Optical microscope (OM) photographs verified the well dispersed ordered intercalated assembles layers of bentonite in PU matrix. [Copyright &y& Elsevier]
- Published
- 2010
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30. XRD pattern of chitin based polyurethane bio-nanocomposites
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Zia, Khalid Mahmood, Zuber, Mohammad, Barikani, Mehdi, Jabbar, Abdul, and Khosa, Muhammad Kaleem
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CHITIN , *POLYURETHANES , *X-ray diffraction , *NANOCOMPOSITE materials , *EMULSION polymerization , *BENTONITE , *ENTHALPY , *SILICATES - Abstract
Abstract: Chitin based polyurethane bio-nanocomposites (PUBNC) were prepared by emulsion polymerization. The existence of the intercalated clay by polyurethane (PU) in the hybrid was confirmed using X-ray diffraction (XRD), dynamic mechanical measurements and optical microscope (OM) techniques. The values of enthalpies changes (ΔH) associated with different bentonite nanoclay contents are much consistent with the crystalline pattern of the synthesized PUBNC samples. These results revealed that pure silicate disappear in PU/bentonite nanoclay hybrid and a set of new peaks appears corresponding to the basal spacing of PU/bentonite clay bio-nanocomposites. The values of tan δ versus temperature recorded using dynamic mechanical measurements were also in accord with crystalline pattern of the PUBNC samples. [Copyright &y& Elsevier]
- Published
- 2010
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31. Surface characteristics of UV-irradiated chitin-based shape memory polyurethanes
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Zia, Khalid Mahmood, Zuber, Mohammad, Mahboob, Shahid, Sultana, Tayyaba, and Sultana, Salma
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POLYURETHANES , *SHAPE memory effect , *SURFACE energy , *ULTRAVIOLET radiation , *LACTONES , *POLYETHYLENE glycol , *ISOCYANATES , *ORGANIC synthesis - Abstract
Abstract: Shape memory polyurethanes (SMPUs) were prepared from polycaprolactone diol 4000 (PCL 4000), 4,4′-diphenylmethane diisocyanate (MDI), 1,4-butanediol (BDO), chitin, dimethylol propionic acid (DMPA), and triethylamine (TEA). The synthesized samples were irradiated for 50, 100, and 200h in an UV exposure unit. The effects of chitin and DMPA contents in the polyurethane (PU) formulation on surface properties of the UV-irradiated PU samples were investigated by contact angle measurements, surface free energy and water absorption (%), total work of water adhesion to polymer and equilibrium degree of swelling. Results of the aforementioned surface techniques revealed that the UV-irradiated PU samples were affected by varying the UV exposure period. The interactions of the PU films with solvents on the surface were clearly related to the contents of DMPA and chitin in the final polyurethane formulation and UV-irradiation time. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
32. Evaluation of biocompatibility and mechanical behavior of chitin-based polyurethane elastomers. Part-II: Effect of diisocyanate structure
- Author
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Zia, Khalid Mahmood, Zuber, Mohammad, Bhatti, Ijaz Ahmad, Barikani, Mehdi, and Sheikh, Munir Ahmad
- Subjects
- *
POLYURETHANE elastomers , *CHITIN , *BIOMEDICAL materials , *BIOCOMPATIBILITY - Abstract
Abstract: Chitin-based polyurethane elastomers having potential for biomedical applications with tunable mechanical properties were synthesized by step growth polymerization techniques using poly(ɛ-caprolactone) (PCL) with different diisocyanates. The prepolymer was extended using chitin and/or 1,4-butane diol (BDO). The structures of the resulted polymers were determined by Fourier transform infrared (FTIR), 1H NMR and 13C NMR spectroscopic techniques. The effect of structure of diisocyanates and chain extenders on mechanical properties and in vitro biocompatibility were investigated. The results revealed that the final polymers extended with chitin are preferred candidates for surgical threads with on going investigations into their in vitro biocompatibility and non-toxicity. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
33. Evaluation of biocompatibility and mechanical behavior of polyurethane elastomers based on chitin/1,4-butane diol blends
- Author
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Zia, Khalid Mahmood, Zuber, Mohammad, Bhatti, Ijaz Ahmad, Barikani, Mehdi, and Sheikh, Munir Ahmad
- Subjects
- *
CHITIN , *BUTANE , *POLYURETHANES , *ELASTOMERS - Abstract
Abstract: Chitin based polyurethane elastomers with potential as biomedical implants with tunable mechanical properties were synthesized by step growth polymerization techniques using poly(ɛ-caprolactone) (PCL) and 4,4′-diphenylmethane diisocyanate (MDI). The prepolymer was extended with different mass ratios of chitin and 1,4-butane diol (BDO). Molecular characterization was done using FTIR, 1H NMR and 13C NMR techniques. The mechanical properties of these polymers were improved with increase in the chitin contents. Optimum mechanical properties were obtained from elastomers extended with chitin in comparison to elastomers extended with BDO. Cytotoxicity of the synthesized polyurethane samples was affected by varying the chitin contents in the chemical composition of the final polyurethane (PU). It is revealed that the final polymers extended with chitin are preferred candidates for surgical threads with on going investigations into their in vitro biocompatibility and non-toxicity. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
34. Morphological and thermal studies of chitin-curcumin blends derived polyurethanes.
- Author
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Mahmood, Kashif, Zia, Khalid Mahmood, Zuber, Mohammad, Tabasum, Shazia, Rehman, Saima, Zia, Fatima, and Noreen, Aqdas
- Subjects
- *
CHITIN , *POLYURETHANES , *FOURIER transform infrared spectroscopy , *HEXAMETHYLENE diisocyanate , *SCANNING electron microscopy - Abstract
The present study describes a novel ecofriendly series of chitin/curcumin/1,4-butane diol (BDO) blend derived polyurethanes (PUs), using hydroxy terminated polybutadiene (HTPB) and hexamethylene diisocyanate (HDI) along with different mole ratio of chitin, curcumin and BDO. The structural and morphological elucidation of the prepared films was done by FTIR and SEM techniques. The swelling behavior of the films was analyzed in both water and DMSO, which showed that incorporation of chitin increases the hydrophobicity and decreases the rate of swelling. Thermal analysis of synthesized PU blends revealed better thermal stability with following mole ratio 1:0.5:0.5 of chitin: curcumin: BDO as determined by TGA and DSC techniques. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
35. Study of the UV protective and antibacterial properties of aqueous polyurethane dispersions extended with low molecular weight chitosan.
- Author
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Muzaffar, Shazia, Bhatti, Ijaz Ahmad, Zuber, Mohammad, Bhatti, Haq Nawaz, and Shahid, Muhammad
- Subjects
- *
CHITOSAN , *POLYURETHANES , *ANTIBACTERIAL agents , *ULTRAVIOLET filters , *SCANNING electron microscopy , *THERAPEUTICS - Abstract
A series of aqueous dispersions of polyurethane (PU) and low molecular weight chitosan (CS (LMW) ) has been prepared in two steps synthetic process. In first step PU prepolymer, with NCO termini were prepared by reacting isophrone diisocyanate (IPDI), poly (caprolactone) diol (CAPA, Mn 1000), and 2,2-dimethylol propionic acid (DMPA), followed by neutralization of PU prepolymer with triethylamine (TEA). In second step PU prepolymer chain was extended by low molecular weight chitosan followed by dispersion formation by adding calculated volume of water. Molecular characterization of CS (LMW) -PU finishes was done by FTIR and application on poly-cotton blended fabric samples was confirmed by scanning electron microscopy (SEM). Antimicrobial and UV protective performance of treated fabrics was performed by AATCC 100 and AATCC TM183 methods respectively. Furthermore, it shows that the addition of chitosan remarkably increases antimicrobial and UV protective properties of PUs. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
36. Synthesis, characterization and efficiency evaluation of chitosan-polyurethane based textile finishes.
- Author
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Muzaffar, Shazia, Bhatti, Ijaz Ahmad, Zuber, Mohammad, Bhatti, Haq Nawaz, and Shahid, Muhammad
- Subjects
- *
TEXTILE finishing , *CHITOSAN , *POLYURETHANES , *ISOPHORONE , *PREPOLYMERS , *MOLECULAR weights - Abstract
A series of polyurethane dispersions were synthesized through two step polymerization technique. A PU prepolymer with NCO termini was prepared using isophorone diisocyanate (IPDI), poly caprolactone diols (CAPA of mol. wt. 1000) and DMPA (3:1:1), and PU prepolymer chain was extended with different mole ratios of low molecular weight chitosan and finally aqueous emulsion was prepared by adding suitable volume of water. The proposed structure of chitosan based PU dispersions was confirmed through FTIR spectroscopy. The prepared aqueous CS (LMW) -CPUIs emulsions were applied onto the different quality plain weave poly-cotton dyed and printed fabric pieces using pad-dry-cure procedures. The physical properties such as air permeability, stiffness and crease recovery angle (CRA), pilling resistance, tear and tensile strength of the treated and untreated fabric samples were also evaluated. The results revealed that the incorporation of chitosan has pronounced effect on the properties of treated fabrics. This research could be extended in future for performance evaluation of pure cotton and woolen fabrics. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
37. Synthesis and characterization of chitosan/curcumin blends based polyurethanes.
- Author
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Zia, Fatima, Zia, Khalid Mahmood, Zuber, Mohammad, Rehman, Saima, Tabasum, Shazia, and Sultana, Salma
- Subjects
- *
POLYURETHANES , *POLYMERIZATION , *CHITOSAN , *CURCUMIN , *HEXAMETHYLENE diisocyanate , *MOLECULAR structure - Abstract
In this work, new hexamethylene diisocyanate (HMDI) and hyroxylterminated polybutadiene (HTPB) based polyurethanes (PUs) were prepared following step growth polymerization by the introduction of varying mole ratio of chitosan (CH) and curcumin (CUR). Structural study of blends through infrared spectroscopy confirmed the incorporation of CH and CUR into the backbone of the PU. The scanning electron microscopic (SEM) study confirmed the well dispersion of incorporated chitosan/curcumin and homogeneity of surface of synthesized samples. Thermogravimetric analysis (TGA) of PU blends indicated a better thermal stability with 0.25 M:0.75 M of chitosan to curcumin. Mechanical properties such as modulus and tensile strength of PU blends were found to be better with higher contents of chitosan and curcumin. The same extender composition (1 mol BDO, 075 mol chitosan and 0.25 mol curcumin) based PU showed higher substantial of antimicrobial activity as compared to the all other PUs. On the whole, this work is actually a step towards the generation of novel biocompatible materials preferably useful for biomedical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
38. Chitosan functionalized poly(vinyl alcohol) for prospects biomedical and industrial applications: A review.
- Author
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Rafique, Ammara, Mahmood Zia, Khalid, Zuber, Mohammad, Tabasum, Shazia, and Rehman, Saima
- Subjects
- *
CHITOSAN , *POLYVINYL alcohol , *INDUSTRIAL applications , *POLYSACCHARIDES , *CHITIN , *BIODEGRADATION - Abstract
Chitin and chitosan are amino polysaccharides having multidimensional properties, such as biocompatibility, biodegradability, antibacterial properties and non-toxicity, muco-adhesivity, adsorption properties, etc., and thus they can be widely used in variety of areas. Although human history mainly relies on the biopolymers, however synthetic materials like polyvinyl alcohol (PVA) have good mechanical, chemical and physical properties. Functionalization of PVA with chitin and chitosan is considered very appropriate for the development of well-designed biomaterials such as biodegradable films, for membrane separation, for tissue engineering, for food packaging, for wound healing and dressing, hydro gels formation, gels formation, etc. Considering versatile properties of the chitin and chitosan, and wide industrial and biomedical applications of PVA, this review sheds a light on chitin and chitosan based PVA materials with their potential applications especially focusing the bio-medical field. All the technical scientific issues have been addressed highlighting the recent advancement. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
39. Glucomannan based polyurethanes: A critical short review of recent advances and future perspectives.
- Author
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Zia, Fatima, Zia, Khalid Mahmood, Zuber, Mohammad, Ahmad, Hafiz Badaruddin, and Muneer, MajId
- Subjects
- *
GLUCOMANNAN , *POLYURETHANES , *BIOPOLYMERS , *POLYSACCHARIDES , *MANNANS - Abstract
Polysaccharides derived from plants are one of the largest groups of natural compounds that offer potentially beneficial functions and properties. Glucomannan, a bioactive polymer belonged to mannan family of polysaccharides is fairly abundant in nature along with superior gelling and film forming properties. Glucomannan and its derivative with several synthetic polymers are used in a biomedical and food sector especially. Polyurethanes (PUs), a commercially useful class of polymers are extensively used in both industry and everyday life because they retain exceptional properties of both plastics and elastomers. This review addresses the properties and applications of glucomannan based materials with the aim to be explored this less attempted polymer further. Furthermore this paper also presents an overview of current status and perspectives of glucomannan based polyurethane materials. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
40. A critical review of algal biomass: A versatile platform of bio-based polyesters from renewable resources.
- Author
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Noreen, Aqdas, Zia, Khalid Mahmood, Zuber, Mohammad, Ali, Muhammad, and Mujahid, Mohammad
- Subjects
- *
BIOMASS , *POLYESTERS , *RENEWABLE natural resources , *ALGAL cells , *POLYMERIZATION , *CARBON dioxide fixation - Abstract
Algal biomass is an excellent renewable resource for the production of polymers and other products due to their higher growth rate, high photosynthetic efficiency, great potential for carbon dioxide fixation, low percentage of lignin and high amount of carbohydrates. Algae contain unique metabolites which are transformed into monomers suitable for development of novel polyesters. This review article mainly focuses on algal bio-refinery concept for polyester synthesis and on exploitation of algae-based biodegradable polyester blends and composites in tissue engineering and controlled drug delivery system. Algae-derived hybrid polyester scaffolds are extensively used for bone, cartilage, cardiac and nerve tissue regeneration due to their biocompatibility and tunable biodegradability. Microcapsules and microspheres of algae-derived polyesters have been used for controlled and continuous release of several pharmaceutical agents and macromolecules to produce humoral and cellular immunity with efficient intracellular delivery. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
41. Chitin and chitosan based polyurethanes: A review of recent advances and prospective biomedical applications.
- Author
-
Usman, Ali, Zia, Khalid Mahmood, Zuber, Mohammad, Tabasum, Shazia, Rehman, Saima, and Zia, Fatima
- Subjects
- *
CHITIN , *POLYURETHANES , *CHITOSAN , *BIOACTIVE compounds , *STRUCTURE-activity relationships - Abstract
Chitin and chitosan are amino polysaccharides having massive structural propensities to produce bioactive materials with innovative properties, functions and diverse applications particularly in biomedical field. The specific physico-chemical, mechanical, biological and degradation properties offer efficient way to blend these biopolymers with synthetic ones. Polyurethane (PU) gained substantial attention owing to its structure-properties relationship. The immense activities of chitin/chitosan are successfully utilized to enhance the bioactive properties of polyurethanes. This review shed a light on chitin and chitosan based PU materials with their potential applications especially focusing the bio-medical field. All the technical scientific issues have been addressed highlighting the recent advancement in the biomedical field. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
42. Heparin based polyurethanes: A state-of-the-art review.
- Author
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Zia, Fatima, Zia, Khalid Mahmood, Zuber, Mohammad, Tabasum, Shazia, and Rehman, Saima
- Subjects
- *
POLYURETHANES , *HEPARIN , *BIOMATERIALS , *BIOCOMPATIBILITY , *GLYCOSAMINOGLYCANS , *ANTICOAGULANTS - Abstract
Polyurethanes (PUs) are considered currently as one of the established bio compatible and blood compatible biomaterials offering tremendous structure–property relationship. But few limitations such as low resistance to micro-emboli and thrombi are still associated with these biomaterials that restricted their applications and hence need to be modified. Heparin, a highly sulfonated and negatively charged member of glycosaminoglycan family is well established for their anti-thrombin, anticoagulant and many biological activities that make it a highly attractive candidate capable of modifying or tailoring polymer properties. Incorporation of heparin for the improvement of biocompatibility of PUs is an interesting approach and enabling emerging technology. This review focuses on the methods used for modification of PUs via heparin with their pros and cons. The major PU–heparin systems with the recent developments and their possible biomedical applications are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
43. Recent developments and future prospects on bio-based polyesters derived from renewable resources: A review.
- Author
-
Zia, Khalid Mahmood, Noreen, Aqdas, Zuber, Mohammad, Tabasum, Shazia, and Mujahid, Mohammad
- Subjects
- *
POLYESTERS , *RENEWABLE natural resources , *PETROLEUM chemicals , *GREENHOUSE gases , *COST effectiveness , *DRUG delivery systems , *PRICES - Abstract
A significantly growing interest is to design a new strategy for development of bio-polyesters from renewable resources due to limited fossil fuel reserves, rise of petrochemicals price and emission of green house gasses. Therefore, this review aims to present an overview on synthesis of biocompatible, biodegradable and cost effective polyesters from biomass and their prospective in different fields including packaging, coating, tissue engineering, drug delivery system and many more. Isosorbide, 2,4:3,5-di-O-methylene- d -mannitol, bicyclic diacetalyzed galactaric acid, 2,5-furandicarboxylic acid, citric, 2,3-O-methylene l -threitol, dimethyl 2,3-O-methylene l -threarate, betulin, dihydrocarvone, decalactone, pimaric acid, ricinoleic acid and sebacic acid, are some important monomers derived from biomass which are used for bio-based polyester manufacturing, consequently, replacing the petrochemical based polyesters. The last part of this review highlights some recent advances in polyester blends and composites in order to improve their properties for exceptional biomedical applications i.e. skin tissue engineering, guided bone regeneration, bone healing process, wound healing and wound acceleration. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
44. Starch based polyurethanes: A critical review updating recent literature.
- Author
-
Zia, Fatima, Zia, Khalid Mahmood, Zuber, Mohammad, Kamal, Shagufta, and Aslam, Nosheen
- Subjects
- *
POLYURETHANES , *RENEWABLE energy sources , *STARCH , *POLYMERS industry , *MATERIALS science , *BIOMASS energy - Abstract
Recent advancements in material science and technology made it obvious that use of renewable feed stock is the need of hour. Polymer industry steadily moved to get rid of its dependence on non-renewable resources. Starch, the second largest occurring biomass (renewable) on this planet provides a cheap and eco-friendly way to form huge variety of materials on blending with other biodegradable polymers. Specific structural versatility design for individual application and tailor-made properties have established the polyurethane (PU) as an important and popular class of synthetic biodegradable polymers. Blending of starch with polyurethane is relatively a developing area in PU chemistry but with lot of attraction for researchers. Herein, various starch based polyurethane materials including blends, grafts, copolymers, composites and nano-composites, as well as the prospects and latest developments are discussed. Additionally, an overview of starch based polymeric materials, including their potential applications are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
45. Recent developments in curcumin and curcumin based polymeric materials for biomedical applications: A review.
- Author
-
Mahmood, Kashif, Zia, Khalid Mahmood, Zuber, Mohammad, Salman, Mahwish, and Anjum, Muhammad Naveed
- Subjects
- *
CURCUMIN , *MEDICAL polymers , *TURMERIC , *ANTI-inflammatory agents , *SPICES , *ANTIOXIDANT analysis - Abstract
Turmeric ( Curcuma longa ) is a popular Indian spice that has been used for centuries in herbal medicines for the treatment of a variety of ailments such as rheumatism, diabetic ulcers, anorexia, cough and sinusitis. Curcumin (diferuloylmethane) is the main curcuminoid present in turmeric and responsible for its yellow color. Curcumin has been shown to possess significant anti-inflammatory, anti-oxidant, anti-carcinogenic, anti-mutagenic, anticoagulant and anti-infective effects. This review summarizes and discusses recently published papers on the key biomedical applications of curcumin based materials. The highlighted studies in the review provide evidence of the ability of curcumin to show the significant vitro antioxidant, diabetic complication, antimicrobial, neuroprotective, anti-cancer activities and detection of hypochlorous acid, wound healing, treatment of major depression, healing of paracentesis, and treatment of carcinoma and optical detection of pyrrole properties. Hydrophobic nature of this polyphenolic compound along with its rapid metabolism, physicochemical and biological instability contribute to its poor bioavailability. To redress these problems several approaches have been proposed like encapsulation of curcumin in liposomes and polymeric micelles, inclusion complex formation with cyclodextrin, formation of polymer–curcumin conjugates, etc. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
46. Alginate based polyurethanes: A review of recent advances and perspective.
- Author
-
Zia, Khalid Mahmood, Zia, Fatima, Zuber, Mohammad, Rehman, Saima, and Ahmad, Mirza Nadeem
- Subjects
- *
POLYURETHANES , *ALGINATES , *BLOCK copolymers , *HYDROGELS , *BIOCOMPATIBILITY , *BIODEGRADABLE nanoparticles - Abstract
The trend of using biopolymers in combination with synthetic polymers was increasing rapidly from last two or three decades. Polysaccharide based biopolymers especially starch, cellulose, chitin, chitosan, alginate, etc. found extensive applications for different industrial uses, as they are biocompatible, biodegradable, bio-renewable resources and chiefly environment friendly. Segment block copolymer character of polyurethanes that endows them a broad range of versatility in terms of tailoring their properties was employed in conjunction with various natural polymers resulted in modified biomaterials. Alginate is biodegradable, biocompatible, bioactive, less toxic and low cost anionic polysaccharide, as a part of structural component of bacteria and brown algae (sea weed) is quite abundant in nature. It is used in combination with polyurethanes to form elastomers, nano-composites, hydrogels, etc. that especially revolutionized the food and biomedical industries. The review summarized the development in alginate based polyurethanes with their potential applications. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
47. Synthesis and molecular characterization of chitosan based polyurethane elastomers using aromatic diisocyanate.
- Author
-
Zia, Khalid Mahmood, Anjum, Sohail, Zuber, Mohammad, Mujahid, Muhammad, and Jamil, Tahir
- Subjects
- *
CHITOSAN , *POLYURETHANE elastomers , *AROMATIC compounds , *POLYMERIZATION , *FOURIER transform infrared spectroscopy - Abstract
Highlights: [•] New chitosan based polyurethane elastomers (PUEs) were synthesized. [•] Molecular engineering was carried out during the synthesis using FT-IR. [•] The FT-IR confirms the existence of the proposed chitosan based PUEs structure. [•] Internal morphology of the prepared PUEs was studied using SEM analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
48. Chitin based polyurethanes using hydroxyl terminated polybutadiene. Part I: Molecular engineering.
- Author
-
Zia, Khalid Mahmood, Mahmood, Kashif, Zuber, Mohammad, Jamil, Tahir, and Shafiq, Muhammad
- Subjects
- *
POLYURETHANES , *CHITIN , *POLYBUTADIENE , *PREPOLYMERS , *TOLUENE diisocyanate , *FOURIER transform infrared spectroscopy , *SCANNING electron microscopes - Abstract
Abstract: Chitin based polyurethanes (PUs) using hydroxyl terminated polybutadiene (HTPB) as soft segment were prepared and the structure of the proposed PU was confirmed using FTIR spectrometer. PU prepolymer was prepared using HTPB and toluene-2,4-diisocyanate (TDI), and the chain was extended with different proportions of 1,4-butane diol (BDO) and chitin. During the detailed FTIR study, it was observed that tri-functional character of chitin results in the formation of network structure due to crosslinking of the material, whereas bi-functional aliphatic diol based polyurethane produced linear PU. Hydrogen bonding between the hard segments was identified by the IR spectroscopy. The scanning electron microscope (SEM) analysis also confirmed the cross-linked structure. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
49. Aflatoxins contamination in peanut and peanut products commercially available in retail markets of Punjab, Pakistan
- Author
-
Iqbal, Shahzad Zafar, Asi, Muhammad Rafique, Zuber, Mohammad, Akram, Noreen, and Batool, Nitasha
- Subjects
- *
AFLATOXINS , *PEANUT products , *PEANUTS , *RURAL industries , *HIGH performance liquid chromatography - Abstract
Abstract: A total 198 peanut and peanut products, commercially available in major cities of Punjab Pakistan were analyzed for aflatoxins (AFs) using HPLC equipped with florescence detector. The data revealed that 59% raw peanut with shell, 55% raw peanut without shell, 61% roasted peanut with shell, 68% roasted peanut without shell, 50% peanut butter, 42% peanut cookies and 20% peanut nimko were found contaminated with AFs. The mean concentration in raw peanut shell was (6.4 μg/kg), raw peanut without shell (9.6 μg/kg), roasted peanut with and without shell (10.4 and 12.3 μg/kg), peanut butter (2.4 μg/kg), peanut cookies (4.6 μg/kg) and peanut nimko (3.4 μg/kg). The present study was a first report on the occurrence of AFs contamination in peanut and peanut products from the markets of Punjab, Pakistan. The level of AFs in peanut and peanut products is high and poses a significant threat for the health of people. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
50. Natural occurrence of aflatoxins and ochratoxin A in commercial chilli and chilli sauce samples
- Author
-
Iqbal, Shahzad Zafar, Asi, Muhammad Rafique, Zuber, Mohammad, Akhtar, Javed, and Jawwad Saif, Muhammad
- Subjects
- *
AFLATOXINS , *OCHRATOXINS , *SAMPLES (Commerce) , *HOT pepper sauces , *PEPPERS , *RESTAURANTS - Abstract
Abstract: Total 170 samples of chillies (chilli sauce, crushed chilli and powdered chilli) were analyzed by HPLC coupled with fluorescence detector. AFs were detected in 39, 59 and 56% of chilli sauce, crushed chilli and chilli powder samples from open market compared with 29, 54 and 58% samples respectively, from food restaurants. OTA was found 5 (19%), 11 (38%) and 13 (38%), in chilli sauce, crushed chilli and chilli powder from open market compared to 4 (17%), 14 (50%), and 12 (41%) samples respectively, from food restaurants. About 12, 27 and 35% chilli sauce, crushed chilli and powdered chilli samples from open market were found above the European Union (EU) limit for total AFs compared to 8, 32, and 41% samples from food restaurants. The daily intakes of AFs and OTA were 3.3 and 2 μg/kg, respectively. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
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