scholarly journals Sodium Polyacrylate as a Super Absorbent

2021 ◽  
pp. 74-84
Author(s):  
Umarfarooq A Halyal
Keyword(s):  
Research Work ◽  
Monomer Concentration ◽  
Polymerization Temperature ◽  
Sodium Polyacrylate ◽  
Practical Applications ◽  
Monomer Composition ◽  
Emulsion Gel ◽  
Synthesis Properties ◽  
Swelling Characteristics ◽  
Rate Of Absorption

This work is devoted to the study of synthesis, properties and practical Applications of class of acrylic-based sodium Polyacrylate superabsorbent polymers. The techniques of solution, emulsion/gel polymerization were used for synthesis. Each absorbent was mainly characterized by its equilibrium capacity of water absorption and by the rate of absorption. The swelling characteristics of the polymers were evaluated in terms of change in polymerization variables which include, type and amount of cross linker, monomer composition, and process of polymerization, temperature, initiator concentration, monomer concentration, Rate of agitation and particle size of the product. The swelling dependency on salinity, ionic strength and PH was also examined. The rapid growing nanotechnology has led to more explorations of SAPs and SAPCs for applications in biomedical, biotechnology and advanced technologies. Examples of research work of SAPs and SAPCs published in refereed, reviewed articles are referred.

Zn diffusion and reflow behaviour of Sn-9Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga solders on a Ni/Cu substrate under IR reflow

2014 ◽  
Vol 26 (2) ◽  
pp. 87-95 ◽  
Author(s):  
J. Mittal ◽  
K.L. Lin
Keyword(s):  
Theoretical Calculations ◽  
Research Work ◽  
Content Type ◽  
Diffusion Behavior ◽  
Zn Diffusion ◽  
Cu Substrate ◽  
Practical Applications ◽  
Substrate Interface ◽  
Solder Balls ◽  
Practical Implications

Purpose – This paper aims to compare the reflow and Zn diffusion behaviors in Sn-Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga (5E) solders during soldering on a Ni/Cu substrate under infrared (IR) reflow. The study proposes a model on the effect of various elements particularly Zn diffusion behavior in the solders on the formation of intermetallic compounds (IMCs). Design/methodology/approach – The melting activities of two solders near their melting points on copper substrates are visualized in an IR reflow furnace. Reflowed solder joints were analyzed using scanning electron microscope and energy dispersive X-ray spectroscopy. Findings – Reflow behaviors of the solders are similar. During melting, solder balls are first merged into each other and then reflow on the substrate from top to bottom. Both solders show a reduced amount of Zn in the solder. Theoretical calculations demonstrate a higher Zn diffusion in the 5E solder; however, the amount of Zn actually observed at the solder/substrate interface is lower than Sn-9Zn solder due to the formation of ZnAg3 in the solder. A thinner IMC layer is formed at the interface in the 5E solder than the Sn-Zn solder. Research limitations/implications – The present work compares the 5E solder only with Sn-Zn solder. Additional research work may be required to compare 5E solder with other solders like Sn-Ag, SnAgCu, etc. to further establish its practical applications. Practical implications – The study ascertains the advantages of 5E solder over Sn-Zn solder for all practical applications. Originality/value – The significance of this paper is the understanding of the relation between reflow behavior of solders and reactivity of different elements in the solder alloys and substrate to form various IMCs and their influence on the formation of IMC layer at solder/substrate interface. Emphasis is provided for the diffusion behavior of Zn during reflow and respective reaction mechanisms.

Comments on the special issue

2018 ◽  
Vol 31 (2) ◽  
pp. 183-212
Author(s):  
Paul McGhee
Keyword(s):  
Physical Health ◽  
Training Program ◽  
Research Work ◽  
Well Being ◽  
Special Issue ◽  
Sense Of Humor ◽  
Practical Applications ◽  
The Brain

Abstract This article includes comments on each contributing author’s article in this special issue of Humor. The articles represent an assessment of McGhee’s research, work on practical applications or influence in the following areas: 1) the development of children’s humor, 2) construction and validation of the Sense of Humor Scale (SHS), 3) usefulness of specific subscales of the SHS, including “playfulness” and “laughing at yourself,” 4) development and evaluation of the 7 Humor Habits Program—a training program for learning to use humor to cope with stress, 5) humor’s impact on physical health and emotional well being, 6) impact on the field of nursing, and 7) humor and the brain. McGhee provides here his response to each contributed article.

Polymerization of n-butyl methylacrylate using bis(β- ketoamino)nickel(II)/MAO catalytic systems

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaohui He ◽  
Yiwang Chen ◽  
Yongming Liu ◽  
Muqing Chen ◽  
Shuxian Yu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Polymerization Temperature ◽  
Moderate Activity ◽  
Polymerization Time ◽  
Catalytic Systems ◽  
Molecular Weights ◽  
Molar Ratios ◽  
Broad Molecular Weight Distribution ◽  
C Nmr

AbstractThe polymerizations of n-butyl methylacrylate (nBMA) were carried out using bis(β-ketoamino)nickel(II) complexes (Ni[CH3C(O)CHC(NR)CH3]2: R = phenyl, 1; R = naphthyl, 2) in combination with methylaluminoxane (MAO) in toluene. The effect of parameters such as polymerization temperature, Al/Ni molar ratios, polymerization time, and monomer concentration, on catalytic polymerization activity and polymer molecular weights, were examined in detail. Both of the nickel(II) catalytic systems exhibited moderate activity, and produced P(nBMA) with high molecular weight and relatively broad molecular weight distribution (Mw/Mn=2.0~3.0. The obtained polymer has been characterized by means of FTIR, 1H NMR, 13C NMR, DSC, and WAXD technique and was confirmed to be syndio-rich stereospecific P(nBMA).

Synthesis and Characterization of Zirconium Metal Complexes Derived from Benzene-1, 4-dicarboxylic acid

2020 ◽  
Vol 42 (6) ◽  
pp. 919-919
Author(s):  
Hafiz Muhammad Arshad Hafiz Muhammad Arshad ◽  
Shazia Khurshid Shazia Khurshid ◽  
Shahzad Sharif Shahzad Sharif ◽  
Muhammad Ali Muhammad Ali ◽  
Muhammad Dilshad Muhammad Dilshad ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Dicarboxylic Acid ◽  
Terephthalic Acid ◽  
Research Work ◽  
Early Developmental Stage ◽  
Practical Applications ◽  
Secondary Building Units ◽  
Ft Ir ◽  
Zirconium Metal

Amongst organo-metallic frameworks (OMFs), the metallic framework having Zirconium metal indicate fascinating structural properties and excellent stability. Such organo-metallic frameworks (OMFs) function as a potential material for practical application. Even though these particular organo-metallic frameworks are in the early developmental stage but considerable advancements have been carried out recently. We studied the characterization of zirconium-based organo-metallic frameworks. We built Zr-based OMFs by four different synthetic ways. Initially, upgraded preparation under green and commercially feasible conditions has been carried out by modifying Zr-OMFs. Zirconium based OMFs having different structures are then classified and explained based on various organic ligands and zirconium-based secondary building units. We have synthesized the zirconium metal complexes; they have been characterized on the bases of FT-IR and CHNS analyzer. FT-IR results show binding of metal with the Benzene-1, 4-dicarboxylic acid [C6H4 (COOH) 2]. Zirconium metal can bind with the organic substances for the construction of a variety of complexes. From my research work, it is concluded that zirconium metal forms a polymeric complex with terephthalic acid. In which oxygen atoms of Terephthalic acid form bridging structure with the zirconium metal. Our study based on a particular type of OMF is likely expected to present guidance for in-depth exploration of OMFs towards practical applications. It is concluded that the metal-organic frameworks (MOFs) of zirconium metal have many applications in the field of chemistry, biology and other numerous fields of science

Discussion of “Passive Control of Building Response Using Energy Dissipating Cladding Connections” by J. P. Pinelli, J. I. Craig, G. J. Goodno, and C. C. Hsu

1994 ◽  
Vol 10 (2) ◽  
pp. 439-446
Author(s):  
Julie Mark Cohen
Keyword(s):  
Structural Engineering ◽  
Passive Control ◽  
Systems Approach ◽  
Research Work ◽  
Building Design ◽  
Practical Applications ◽  
Building Systems ◽  
Integral Role ◽  
Architectural Research

The authors should be commended for their pioneering research work on structural cladding and energy-dissipating connections. This discussion has been written to help ensure that this research, which is multidisciplinary in nature, leads to practical applications. All structural engineering researchers must recognize that structural cladding design is one of the broadest building-related research topics that can be tackled. They should not focus only on topics that have roots in structural engineering alone, and thus deny the integral role of structural cladding in building design. The importance of a building systems approach must be recognized. In doing so, the role of the architect will become obvious, and a promising collaborative effort will be established. This discussion is made from the perspective of a background in structural engineering and architectural research and practice.

The Effects of Initiating Systems on CPAM Relative Molecular Weight and Strength Properties of Paperboard

2013 ◽  
Vol 821-822 ◽  
pp. 945-948
Author(s):  
Hui Rong Yang ◽  
Chuan Shan Zhao ◽  
Xue Zhang ◽  
Wen Jia Han
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Strength Properties ◽  
Polymerization Temperature ◽  
Initiator Concentration ◽  
Redox Systems ◽  
Aqueous Polymerization ◽  
Relative Molecular Weight

initiator is one of the most important conditions of synthesizing efficient strength agent CPAM. To begin with initiating mechanism, three redox systems of acrylamide aqueous polymerization (NH4)2S2O8/ Na2SO3, K2S2O8/NaHSO3and K2S2O8/Na2S2O4have been studied. The effects of different kinds of initiator, initiator concentration, and monomer concentration as well as polymerization temperature on relative molecular weight and strength effects of CPAM have been investigated. K2S2O8/Na2SO3is the most useful system in synthesizing efficient strength agents.

scholarly journals A Complexed Initiating System AlCl3·Phenetole/TiCl4·H2O with Dominant Synergistic Effect for Efficient Synthesis of High Molecular Weight Polyisobutylene

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2121
Author(s):  
Yulong Jin ◽  
Liang Chen ◽  
Xing Guo ◽  
Linfeng Xu ◽  
Zhihua Zhu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Synergistic Effect ◽  
High Molecular Weight ◽  
Monomer Concentration ◽  
Catalyst System ◽  
Polymerization Temperature ◽  
Simple Preparation ◽  
Order Of Magnitude ◽  
Unique Approach ◽  
High Molecular Weight Polyisobutylene

A complexed initiating system AlCl3·phenetole/TiCl4·H2O was prepared by simply compounding AlCl3/phenetole and TiCl4/H2O and used for cationic polymerization of isobutylene. It was found AlCl3·phenetole/TiCl4·H2O exhibited activities 1.2–3 times higher than those of AlCl3/phenetole, and more than an order of magnitude higher than those of TiCl4/H2O, which indicated a notable synergistic effect produced in the complexed system. In addition, due to the higher activity of AlCl3·phenetole/TiCl4·H2O, lower coinitiator concentration and polymerization temperature, as well as higher monomer concentration were more favored for this complexed initiating system to produce polyisobutylene (PIB) with reasonable molecular weight (Mw) and molecular weight distribution (MWD). Furthermore, high molecular weight polyisobutylene (HPIB) with Mw = 1–3 × 105 g·mol−1 could be successfully produced by the complexed catalyst system at Tp = −60 to −40 °C. As a whole, the high activity as well as the simple preparation procedures of the complexed initiating system offer us a unique approach for the production of HPIB with improved efficiency.

Water-swellable elastomers: synthesis, properties and applications

2018 ◽  
Vol 35 (1) ◽  
pp. 45-72 ◽  
Author(s):  
Lorenzo M. Polgar ◽  
Francesca Fallani ◽  
Juul Cuijpers ◽  
Patrizio Raffa ◽  
Antonius A. Broekhuis ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Hydrophobic Materials ◽  
Academic Researchers ◽  
Synthesis Properties ◽  
Swelling Characteristics ◽  
Patent Literature ◽  
Difficult Challenge ◽  
Water Swelling ◽  
Synthetic Approaches ◽  
New Applications

Abstract Water-swellable elastomers (WSE) constitute a class of rubbery materials that have been widely studied both in academia and industry during the last 25 years. Market pull is the major driver for the exploration of these materials. The need of WSE in several sealing applications has driven the attention of many academic researchers toward the possibility to provide a rubber with water-swelling characteristics. As commercial rubbers are hydrophobic materials, making them swell in water presents an interesting and difficult challenge. This paper reviews the scientific and patent literature on the fundamental aspects of WSE: the various synthetic approaches, the properties of the corresponding polymers (not only the swelling performance but also the mechanical behavior), and some of their applications. Particular attention is paid to the chemical structure/performance relationships of WSE. Finally, the authors speculate on a great future for WSE that can be rationally designed for improved and/or new applications.

Microstructures of Polydienes Prepared from Alkyllithium

1965 ◽  
Vol 38 (4) ◽  
pp. 863-870
Author(s):  
Heney L. Hsieh
Keyword(s):  
Activation Energy ◽  
Exact Sequence ◽  
Anionic Polymerization ◽  
Monomer Concentration ◽  
Polymerization Temperature ◽  
Micro Structure ◽  
Solvent Type ◽  
Heat Activation ◽  
Stereospecific Polymerization ◽  
Transition Complex

Abstract The stereochemistry of polymerization of isoprene and butadiene by means of alkyllithium initiators was examined. The stereochemistry of polybutadiene and polyisoprene responded to the same variables in anionic polymerization. Micro-structure of both polymers is sensitive to initiator level, solvent type, and polymerization temperature, but is independent of monomer concentration, conversion and initiator structure. The heat activation energy of the reaction leading to 1,2 addition is greater than of that leading to trans-1,4 addition (1200 cal/mole). The exact sequence leading to stereospecific polymerization of dienes by means of alkyllithium is still not clear. However, it seems to involve orientation of the incoming monomer units by association and passage through a transition complex in which all bonds are largely covalent in character and within which polymerization occurs.

scholarly journals Radiolytic synthesis of gold nanoparticles in HEMA-based hydrogels: Potentialities for imaging nanocomposites

Nukleonika ◽  
2021 ◽  
Vol 66 (4) ◽  
pp. 165-177
Author(s):  
Katsiaryna Dziarabina ◽  
Uliana Pinaeva ◽  
Sławomir Kadłubowski ◽  
Piotr Ulański ◽  
Xavier Coqueret
Keyword(s):  
Gold Nanoparticles ◽  
Monomer Conversion ◽  
Thermomechanical Properties ◽  
Temperature Sensitive ◽  
Trimethylammonium Chloride ◽  
Stimuli Responsive ◽  
Monomer Composition ◽  
Swelling Characteristics ◽  
High Degree ◽  
Radiolytic Synthesis

Abstract This article reports on the radiolytic synthesis of nanocomposites containing gold nanoparticles (AuNPs) within two types of hydrogels based on 2-hydroxyethyl methacrylate (HEMA): (i) plain networks with various contents in ethylene glycol dimethacrylate (EGDMA), as a cross-linker and (ii) stimuli-responsive (SR) networks prepared from these monomers copolymerized with [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT) to confer pH-switchable swelling. Hydrogels were prepared by photopolymerization with well-defined composition and a high degree of monomer conversion using two experimental procedures, as xerogels or in aqueous solution. Besides MADQUAT, acrylic acid (AA) or N-isopropylacrylamide have been tested as copolymers, yielding pHor temperature-sensitive hydrogels, respectively. Isothermal swelling in water was affected by monomer composition. Electron beam (EB) irradiation at doses up to 100 kGy of poly(HEMA) xerogels and water-swollen networks prepared with 0.5 wt% of EGDMA had a moderate impact on swelling characteristics and thermomechanical properties of the plain materials, whereas small amounts of extractables were formed. Poly(HEMA)-based nanocomposites containing AuNPs were successfully obtained by EB irradiation of samples swollen by aqueous solutions of Au(III). The effects of dose and cross-linking density on the formation of AuNPs were monitored by UV-visible spectroscopy. Irradiation at well-defined temperatures of the Au(III)-loaded SR hydrogels induced the formation of nanoparticles with size-dependent features, whereas the efficiency of Au(III) reduction at 10 kGy was not significantly affected by the network structure. EB-induced reduction of Au(III) in poly(HEMA) hydrogels using a lead mask to generate well-defined patterns yielded coloured and long-lasting images in the zones where the nanocomposite was formed.

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