Download or read book Synthesis and Characterization of Hydrophobically Modified Twin tailed Associative Polymers Using Micellar Polymerization written by Geoffrey Lawrence Smith and published by . This book was released on 2001 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Hydrophobically Modified Polymers written by Jason Tompkins and published by . This book was released on 1992 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Hydrophobically Modified Polyacrylamide based Polymers and Their Hydrogels written by Yi Yang and published by . This book was released on 1996 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Associating Macromolecules written by Carlton Brent Johnson and published by . This book was released on 1987 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of the Microstructure on the Physico chemical Properties of Multiblock Associative Polymers Synthesized Via RAFT MADIX Micellar Polymerization written by Cécile Barthet and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the middle of the 20th century, enhanced oil recovery (EOR) techniques have been used to improve the extraction of crude oil. Hydrophobically modified polyacrylamides have shown great properties as rheology modifiers for EOR purposes. However, the synthesis of water-soluble polymers containing hydrophobic segments along the backbone is challenging as hydrophilic and hydrophobic monomers are rarely soluble in the same solvent. The aim of this project was to develop acrylamide-based copolymers for enhanced oil recovery (EOR). In this process, long chain polymer molecules are mixed with water and injected into the oil field in order to drive the oil out of the well. The polymer serves to increase the viscosity of the water, making it more effective at displacing the oil. In this thesis, RAFT/MADIX technique has been combined with micellar polymerization in order to synthesize new associative copolymers with controlled architectures and numerous hydrophobic blocks distributed along the backbone. The associations generate a viscoelastic network in aqueous media resulting in a viscosity increase. The combination of RAFT/MADIX with micellar polymerization allows us to limit the compositional drift observed in conventional micellar polymerization. First, the study of the effect of monomers and salts on the behavior of surfactant micelles has shown that the influence of NaAMPS dominates that of acrylamide in its effect on the micellization behavior of SDS. This study has proven that it is possible to predict how NH would vary depending on the composition of the reactive medium during the synthesis. Understanding the surfactant-monomer interactions thus enables prediction of the microstructure of the polymer. In a second step, it has been demonstrated that the associative polymeric chains were living chains and could be further extended to high molar masses with acrylamide. Increasing the content of NaAMPS in the hydrophilic backbone led to a significant increase in the reactivity ratio. The addition of monovalent salt (especially NaCl) is a useful tool to control the polymer microstructure, enabling switching between a gradient-type composition and a more homogeneous one (rhydrophilic monomers/tBS close to 1). Finally, the examination of structure-property relationships of the associative polymers has highlighted that all polymers displayed associating properties as well as enhanced viscosity compared to homopolyacrylamide. The polymer viscosity strongly decreased upon incorporation of NaAMPS within the backbone while it was unaffected by the presence of NaCl during the synthesis. The polymer displaying the best properties for use in EOR is P(Am90-co-AMPS10-co-(Am/NaCl)10-co-tBS1). The use of NaCl ensures good rheological properties while AMPS enhances the solubility of the copolymer.
Download or read book Synthesis and Characterization of Self assembling Polymers Using Hydrogen Bonding Or Hydrophobic Effect written by Xinjun Yu and published by . This book was released on 2015 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is mainly based on the works of synthesis and characterization of self-assembling polymers using hydrogen bonding or hydrophobic interactions. Firstly, N-alkyl urea peptoid oligomer was synthesized as backbone of supramolecular polymers through three step repetition cycles with high yield. One N-alkyl urea peptoid precursor was explored to simplify the synthetic process. 4 different functional groups were converted from one precursor. Then 2-ureido-4[1H]-pyrimidinone (UPy) group which is a quadruple hydrogen bonding system was incorporated to N-alkyl urea peptoid oligomers to generate supramolecules. With the experience of UPy unit, we further explored UPy containing monomer to make organogelators. Three different monomers with different Tg values were copolymerized using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Organogels were afforded in both chloroform and dichlorobenzene. Critical gelation concentration and mechanic properties of organogels were examined. Cooperating another novel monomer containing pyrene unit to the above copolymers, fluorescent organogels were achieved which were suitable for potential up-conversion applications. In addition to pyrene, anthracene is another molecule which shows great up-conversion property. A series of Poly[(9-anthrylmethyl methacrylate)-co-(methyl methacrylate)] (Poly(AnMMA-co-MMA)) with different AnMMA ratios were synthesized via RAFT polymerization, resulting in tunable inter-chromophore distances. These polymers can serve as emitters, with PtOEP as sensitizer, in triplet-triplet annihilation up-conversion (TTA-UC) systems. TTA-UC intensity of the Poly(AnMMA-co-MMA)/PtOEP mixtures displays interesting dependence on the AnMMA ratio in the polymer. Interactions between chromophores on the same polymer chain play the key role in affecting the TTA-UC intensity in these systems. It is critical to minimize intra-chain chromophore quenching in order to achieve high UC intensity. Hydrophobic effect was used to obtain a hybrid photosensitizer. By integrating amphiphilic block copolymer poly(N-isopropylacrylamide-b-styrene) (PNIPAAm-b-styrene) stabilized silver nanoparticles (Ag NPs) with hematoporphyrin (HP), HP was trapped by polystyrene block through hydrophobic effects. Hydrophilic block can increase the solubility of this photosensitizer in aqueous solution. This hybrid photosensitizer was demonstrated to enhance singlet oxygen production. Finally, a self-immolative polymer was made with a kinetically stable polymer backbone, whose chain end can respond to external stimulus by triggering a head-to-tail depolymerizaiton. Electrospining was used to fabricate nano-scale fibers which can be utilized in potential drug delivery system.
Download or read book Papers Presented at the Meeting written by American Chemical Society. Division of Polymer Chemistry and published by . This book was released on 1998 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 2000 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Characterization of Hydrophobically Associating Water soluble Polymers written by Frank Sy-Yih Hwang and published by . This book was released on 1993 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Polymers Incorporating N alkyl Urea peptoid Sequences written by Xiaoping Chen and published by . This book was released on 2013 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is mainly based on the works of synthesis and characterization of polymer/N-alkyl urea peptoid hybrid materials. Polymers were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using thrithiocarbonate and dithiocarbonate chain transfer agents in controlled manner. Poly(N-alkyl urea peptoid) was synthesized via step growth polymerization using symmetric diamine and diisocyanate. N-Alkyl urea peptoid sequences up to sixmer were synthesized through three steps repetition cycles in good yields. Several different hybrid polymeric materials were explored combining the three different material synthetic strategies including polymer conjugates shown in chapter 2, molecular brushes shown in chapter 3, water soluble A-B-A triblock copolymer shown in chapter 4. Firstly, two well-defined statistical copolymers poly(styrene-co-3-azidopropyl methacrylate) and poly(3-O-methacryloyl-1,2:5,6-di-O-isopropylidene-[subscript D]-glucofuranose -co-AzPMA) were synthesized by RAFT. An exemplary N-alkyl urea peptoid trimer was synthesized and conjugated to the two copolymers through the 'click' reaction of the azide pendent group of polymers with the complilanry alkene group at N-alkyl urea peptoid. The polymer conjugates were subjected to further post-modification to generated fluorescent conjugates or water soluble materials. Following the explore of conjugation, N-alkyl urea peptoid was used as comonomer to synthesize linear poly(N-alkyl urea peptoid). The RAFT agent was introduced onto the linear polymer generated by step growth polymerization once again through 'click' reaction. Sequentially, styrene and tert-butyl acrylate was grown from RAFT agents sites that fused onto the poly(N-alkyl urea peptoid) backbone to make block copolymer arms. Upon removal of the tert-butyl groups, the molecular brushes were observed to generate micelles in aqueous solution. The self-assembly N-alkyl urea peptoid was then investigated and conjugated to water soluble polymer poly(ethylene glycol) to produce a A-B-A block copolymer that self-assembled into ribbons in aqueous solution. The final two part of dissertation was about gelling materials studies starting with presenting a synthesis strategy for low molecular weight organogelators (LMOG) using the ureidopyrimidinone (UPy) group functioned N-alkyl urea peptoid. The surprising observation of gelation in DMSO led to extensive investigation of the gelification mechanism studies. Based on the lessons of LMOG, the copolymerization of different T[subscript g] monomers with quadruple hydrogen bonding containing methacrylate was demonstrated suitable to produce polymeric organogelators in the final chapter.
Download or read book Synthesis and Characteristics of Hydrophobically Modified Copolyacrylamides with Microheterogeneous Associations in Aqueous Media written by John C. Middleton and published by . This book was released on 1990 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Nano sized Polymer Particles Using Differential Microemulsion Polymerization written by Guangwei He and published by . This book was released on 2006 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Captodatively Stabilized Initators Monomers and Polymers written by David Wayne Kurz and published by . This book was released on 1991 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymeric Surfactants written by Tharwat F. Tadros and published by Walter de Gruyter GmbH & Co KG. This book was released on 2017-05-08 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymeric Surfactants covers the structure and stability origins of these highly useful surfactants. Adsorption and solution properties in emulsions are discussed based on their underlying thermodynamics and kinetics. Research scientists and Ph.D. students investigating chemistry, chemical engineering and colloidal science will benefit from this text on polymeric surfactants and their value in preparation and stabilization of disperse systems.
Download or read book Nanoparticulates as Drug Carriers written by V. P. Torchilin and published by Imperial College Press. This book was released on 2006 with total page 758 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by key experts in the field of nanomedicine, this book provides a broad introduction to the important field of nanomedicine and application of nanotechnology for drug delivery. It covers up-to-date information regarding various nanoparticulate drug delivery systems, describes the various opportunities for the application of nanoparticular drug carriers in different areas of clinical medicine, and analyzes already available information on their clinical applications. This book can be used as an advanced textbook by graduate students and young scientists and clinicians at the early stages of their career. It is also suitable for non-experts from related areas of chemistry, biochemistry, molecular biology, biomedical engineering, physiology, experimental and clinical medicine, and pharmaceutical sciences, who are interested in general problems of drug delivery and drug targeting, as well as in more specialized topics of using nanoparticulate-mediated drug delivery approaches in the individual areas of clinical medicine. Prof Torchilin is an expert in Nanomedicine and a recipient of numerous awards including the Lenin Prize in Science & Technology of the former USSR, membership in the European Academy of Sciences, and AAPS Research Achievement Award in Pharmaceutics and Drug Delivery. He served as an Associate Professor of Radiology at Harvard Medical School before joining Northeastern University as the Chairman of the Department of Pharmaceutical Sciences. Sample Chapter(s). Chapter 1: Introduction. Nanocarriers for Drug Delivery: Needs and Requirements (442 KB). Contents: Nanoparticle Flow: Implications for Drug Delivery (A T Florence); Polymer Micelles as Drug Carriers (E V Batrakova et al.); Lipoproteins as Pharmaceutical Carriers (S Liu et al.); Dendrimers as Nanoparticular Drug Carriers (S Svenson & D A Tomalia); Cells and Cell Ghosts as Drug Carriers (J M Lanao & M L Sayalero); Magnetic Nanoparticles as Drug Carriers (U O Hnfeli & M Chastellain); Liposomal Drug Carriers in Cancer Therapy (A A Gabizon); Delivery of Nanoparticles to the Cardiovascular System (B-A Khaw); Nanoparticles for Targeting Lymphatics (W Phillips); Nanoparticular Carriers for Ocular Drug Delivery (A Sanchez & M J Alonso); and other papers. Readership: Graduate students, academics in nanomedicine, clinicians, pharmacologists, pharmacists, bioengineers, researchers in biotechnology and diagnostic imaging."
Download or read book Cationic Polymers and Amphiphiles Based on 2 aminoethyl Methacrylate written by Fadwa Al-Saffar and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthetic polymers obtained from acrylates and methacrylates have found wide spread use in medicine as drug carriers, functional colloidal particles, biomedical applications, synthesis of polypeptide vesicles and micelles. 2-aminoethyl methacrylate (AMA) is a commercially available amine- based methacrylic polymer from which a series of copolymers were prepared. In this study 2-aminoethyl methacrylate (AMA) was homopolymerised to different degrees of polymerisation using atom transfer radical polymerisation (ATRP) and free radical polymerisation (FRP) to afford a series of different molecular weight polyamines. The polymers were characterised using lH NMR spectroscopy and gel permeation chromatography. The intrinsic viscosities for the polymers synthesised by ATRP and FRP were determined and viscometric constants (Mark Hauwink constants) were calculated. Modification of the polymers was done by conjugating hydrophobic side moieties (cetyl chains) with their primary amino groups to achieve amphiphilies polymers with the ability to self-assemble in aqueous media into supramolecular structures. Characterisation of the modified polymers was done by lH NMR, 13C NMR, IR spectroscopy, and elemental analysis. The ability of the hydrophobically-modified polymers (HMP) to self-assemble in aqueous media was studied using dynamic light scattering (DLS), and it was found that these polymers have the ability to form polymeric micelles, the size was found to depend on solution pH. To investigate the solution properties of these novels HMP, cetylated PAMAs with different degrees of modifications were prepa red. The effect of increasing the molecular weight and degree of hydrophobic substitution on the aggregation behavior of these amphiphliles in aqueous solutions was studied using DLS, and transmission electron microscopy (TEM). The aggregation behavior and critical association concentration were studied using surface tension measurements, and fluorescent spectroscopy using pyrene as a polarity probe. The biocompatibility of the unmodified polymers was assessed using the haemolytic activity assay, and the slug mucosal irritation test (SMIT). It was found that PAMA did not induce detectable haemolysis and the irritancy potential of these polymers.
Download or read book Synthesis and Characterization of Acrylamido based Polymers Via Reversible Addition fragmentation Chain Transfer Polymerization written by Michael Stephen Donovan and published by . This book was released on 2002 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
