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1 Mechanism of the graft copolymerization of AMPS onto Cs. Reproduced with permission from Najjar et al. (2000)
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In recent decades, a series of strategies have been reported for modifing surface properties of natural and synthetic polymers. Among the strategies for the modification of polymers, grafting is considered the most ideal technique. Several monomers with specific physicochemical and surface characteristics can be grafted onto the polymers. Therefore...
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... is a water-soluble free radical initiator. With this in mind, Liu and Sun (2008) reported the free radical graft polymerization process to functionalize the cotton cellulose surface. In line with this, Retuert and Yazdani-Pedram (1993) (Fig. ...
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... sites, which are obtained by clevage the O-H bonds, which are required to achieve the growth chain ( Gabriel et al. 1998;). Some examples are given in Table 8.1. Liu et al. (2005) discussed the MW-assisted copolymerization of caprolactone and Cs by using phthaloyl. Cs was used as a precursor and Sn(Oct) 2 as a catalyst without using any solvent (Fig. 8.10). The Cs-g-poly(ε-caprolactone) (PCL) copolymer obtained with increased hydrophobic units and free amino groups was intended as degradable amphoteric material with potential for various biomedical ...
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... polymer through a free radical mechanism. The free radicals formed on polymer backbone lead to the covalent reaction of the vinyl monomer and propagates a new polymer chain. This chain propagation attributes the formation of new properties of the backbone polymer. The free radical grafting of vinyl and acrylic monomers onto cellulose is shown in Fig. 8.11 (Roy et al. 2009). In another study, Athawale and Lele (1998) prepared a crosslinked network hydrogel by grafting vinyl or AA monomer on granular corn starch under a nitrogen atmosphere, thus obtaining a maximum water absorption rate of 250 g/g. Pourjavadi et al. (2004) also synthesized chemically crosslinked superabsorbent hydrogel via graft ...
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... or AA monomer on granular corn starch under a nitrogen atmosphere, thus obtaining a maximum water absorption rate of 250 g/g. Pourjavadi et al. (2004) also synthesized chemically crosslinked superabsorbent hydrogel via graft copolymerization of AA onto kappa-carrageenan (kC) using MBA as a crosslinking agent and APS as a free radical initiator (Fig. 8.12). Fig. 8.12 Grafting of AA onto kC. Reproduced with permission from Pourjavadi et al. (2004) The Psyllium mucilage was also modified by grafting with AA, using KPS as an initiator and hexamethylenetetramine (HMTA) as a crosslinking agent (Kaith and Kumar 2007). Deshpande (1986) also prepared AA-g-Cs copolymers, using CAN and HNO 3 redox ...
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... on granular corn starch under a nitrogen atmosphere, thus obtaining a maximum water absorption rate of 250 g/g. Pourjavadi et al. (2004) also synthesized chemically crosslinked superabsorbent hydrogel via graft copolymerization of AA onto kappa-carrageenan (kC) using MBA as a crosslinking agent and APS as a free radical initiator (Fig. 8.12). Fig. 8.12 Grafting of AA onto kC. Reproduced with permission from Pourjavadi et al. (2004) The Psyllium mucilage was also modified by grafting with AA, using KPS as an initiator and hexamethylenetetramine (HMTA) as a crosslinking agent (Kaith and Kumar 2007). Deshpande (1986) also prepared AA-g-Cs copolymers, using CAN and HNO 3 redox system ...
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... graft copolymer with binary monomers such as AM/DMDAAC binary monomers was the first to be prepared under the radiation grafting method. This method provided a higher ratio of grafting and efficiency of binary monomers at absorbed doses of 2 kGy and 3 kGy using a 6:9.8:4.2 (w/w/w) ratio of starch/AM/DMDAAC as shown in Fig. 8. 13 (Lv et al. 2013). Fig. 8.13 The gamma radiation-initiated graft copolymerization of AM and DMDAAC onto corn starch. Reproduced with permission from Xiaohua et al. (2013) Kumar et al. (2009) prepared two graft copolymers based on xanthan and PAM through the MW radiation-irradiated method and the other ceric ion-induced graft copolymerization method. These authors ...
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... is a water-soluble free radical initiator. With this in mind, Liu and Sun (2008) reported the free radical graft polymerization process to functionalize the cotton cellulose surface. In line with this, Retuert and Yazdani-Pedram (1993) (Fig. ...
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... sites, which are obtained by clevage the O-H bonds, which are required to achieve the growth chain ( Gabriel et al. 1998;). Some examples are given in Table 8.1. Liu et al. (2005) discussed the MW-assisted copolymerization of caprolactone and Cs by using phthaloyl. Cs was used as a precursor and Sn(Oct) 2 as a catalyst without using any solvent (Fig. 8.10). The Cs-g-poly(ε-caprolactone) (PCL) copolymer obtained with increased hydrophobic units and free amino groups was intended as degradable amphoteric material with potential for various biomedical ...
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... polymer through a free radical mechanism. The free radicals formed on polymer backbone lead to the covalent reaction of the vinyl monomer and propagates a new polymer chain. This chain propagation attributes the formation of new properties of the backbone polymer. The free radical grafting of vinyl and acrylic monomers onto cellulose is shown in Fig. 8.11 (Roy et al. 2009). In another study, Athawale and Lele (1998) prepared a crosslinked network hydrogel by grafting vinyl or AA monomer on granular corn starch under a nitrogen atmosphere, thus obtaining a maximum water absorption rate of 250 g/g. Pourjavadi et al. (2004) also synthesized chemically crosslinked superabsorbent hydrogel via graft ...
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... or AA monomer on granular corn starch under a nitrogen atmosphere, thus obtaining a maximum water absorption rate of 250 g/g. Pourjavadi et al. (2004) also synthesized chemically crosslinked superabsorbent hydrogel via graft copolymerization of AA onto kappa-carrageenan (kC) using MBA as a crosslinking agent and APS as a free radical initiator (Fig. 8.12). Fig. 8.12 Grafting of AA onto kC. Reproduced with permission from Pourjavadi et al. (2004) The Psyllium mucilage was also modified by grafting with AA, using KPS as an initiator and hexamethylenetetramine (HMTA) as a crosslinking agent (Kaith and Kumar 2007). Deshpande (1986) also prepared AA-g-Cs copolymers, using CAN and HNO 3 redox ...
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... on granular corn starch under a nitrogen atmosphere, thus obtaining a maximum water absorption rate of 250 g/g. Pourjavadi et al. (2004) also synthesized chemically crosslinked superabsorbent hydrogel via graft copolymerization of AA onto kappa-carrageenan (kC) using MBA as a crosslinking agent and APS as a free radical initiator (Fig. 8.12). Fig. 8.12 Grafting of AA onto kC. Reproduced with permission from Pourjavadi et al. (2004) The Psyllium mucilage was also modified by grafting with AA, using KPS as an initiator and hexamethylenetetramine (HMTA) as a crosslinking agent (Kaith and Kumar 2007). Deshpande (1986) also prepared AA-g-Cs copolymers, using CAN and HNO 3 redox system ...
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... graft copolymer with binary monomers such as AM/DMDAAC binary monomers was the first to be prepared under the radiation grafting method. This method provided a higher ratio of grafting and efficiency of binary monomers at absorbed doses of 2 kGy and 3 kGy using a 6:9.8:4.2 (w/w/w) ratio of starch/AM/DMDAAC as shown in Fig. 8. 13 (Lv et al. 2013). Fig. 8.13 The gamma radiation-initiated graft copolymerization of AM and DMDAAC onto corn starch. Reproduced with permission from Xiaohua et al. (2013) Kumar et al. (2009) prepared two graft copolymers based on xanthan and PAM through the MW radiation-irradiated method and the other ceric ion-induced graft copolymerization method. These authors ...
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... Graft copolymerization is a commonly used technique to chemically modify natural rubber. It is a well-known method for creating hybrid polymers with distinctive structures required for a variety of applications by employing multiple monomers [14][15][16]. Typical monomers successfully grafted onto NR chains include acrylonitrile (AN) [17], methyl methacrylate (MMA) [18][19][20][21], maleic anhydride (MA) [8,[22][23][24], stearyl methacrylate (SMA) [25,26] and styrene (ST) [12,[27][28][29][30][31]. ...
Natural rubber is biopolymer with high mechanical strength and excellent elasticity, but its main drawback is poor thermal stability. Many techniques have been employed to improve its thermo-mechanical properties. In this study, graft copolymerization of styrene, acrylonitrile onto deproteinized natural rubber using tert-butyl hydroperoxide and tetraethylene pentamine as redox initiator and diimide transfer hydrogenation have been investigated. The structural characterization of the obtained products was carried out by Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy and proton Nuclear Magnetic Resonance. The thermal properties of materials were studied by Thermal Gravimetric Analysis/Differential Thermal Gravimetric Analysis and Differential Scanning Calorimetry. The mechanical properties of the obtained copolymers were confirmed via tensile testing, where the tensile strength of the graft copolymer (DPNR-g-PS.PAN) (3.4 MPa) and hydrogenated-DPNR-g-PS.PAN (H-DPNR-g-PS.PAN) (2.6 MPa), nearly doubled when compared to untreated deproteinized natural rubber (1.5 MPa). The molecular weight distributions of products were determined by Gel Permeation Chromatography, in which the symmetry of molecular weight distribution was improved after each step of the modification.
Carbon dots (CDs), a novel class of carbon-based nanoparticles, have received a lot of interest recently due to their exceptional mechanical, chemical, and fluorescent properties, as well as their excellent photostability and biocompatibility. CDs’ emission properties have already found a variety of potential applications, in which bioimaging and sensing are major highlights. It is widely acknowledged that CDs’ fluorescence and surface conditions are closely linked. However, due to the structural complexity of CDs, the specific underlying process of their fluorescence is uncertain and yet to be explained. Because of their low toxicity, robust and wide optical absorption, high chemical stability, rapid transfer characteristics, and ease of modification, CDs have been recognized as promising carbon nanomaterials for a variety of sensing applications. Thus, following such outstanding properties of CDs, they have been mixed and imprinted onto different polymeric components to achieve a highly efficient nanocomposite with improved functional groups and properties. Here, in this review, various approaches and techniques for the preparation of polymer/CDs nanocomposites have been elaborated along with the individual characteristics of CDs. CDs/polymer nanocomposites recently have been highly demanded for sensor applications. The insights from this review are detailed sensor applications of polymer/CDs nanocomposites especially for detection of different chemical and biological analytes such as metal ions, small organic molecules, and several contaminants.
To overcome the current scarcity of fresh water sustainably, new technologies will be required that produce potable water from a range of sources, including seawater and moisture from the atmosphere. Moreover, we must recover and reuse water from wastewater streams to reduce our global water footprint. To date, there remain significant concerns about the environmental/ecological impact, high energy consumption, and extensive maintenance costs of current technologies that might prevent their transition to more sustainable routes of potable water generation. One class of material that can enable low-energy water production is thermoresponsive polymers. Due to their unique phase behavior, production flexibility, and biocompatibility, these materials may allow for sustainable routes to fresh water in current and new technologies. In this Perspective, we specifically summarize the design and application of poly(N-isopropylacrylamide)- (PNIPAm-) based thermoresponsive microgels and hydrogels. In particular, we show how these materials have been used for water purification, including wastewater treatment, seawater desalination, and moisture harvesting from the atmosphere. Finally, we discuss the opportunities and challenges of transforming current thermoresponsive materials into practical water-related technologies.
