scholarly journals ACRYLIC-CASEIN LATEXES WITH POTENTIAL APPLICATION AS ADHESIVES

2020 ◽  
Vol 50 (2) ◽  
pp. 115-120
Author(s):  
Ana Aguzin ◽  
José Ignacio Jerkovich ◽  
Julieta Trucone ◽  
Ludmila Irene Ronco ◽  
Roque Javier Minari ◽  
...  
Keyword(s):  
Environmental Impact ◽  
Chemical Modification ◽  
Chain Transfer ◽  
Industrial Applications ◽  
New Materials ◽  
Acrylic Polymer ◽  
Molecular Weights ◽  
Variable Content ◽  
A Chain ◽  
Grafting Degree

The replacement of monomers derived from petrochemical sources by biopolymers like proteins, together with the development of new materials with improved properties, have an increasing importance in industrial applications. In this context, the synthesis of acrylic-casein hybrid latexes was investigated through a low environmental impact strategy, such as the surfactant-free emulsion polymerization, with the aim of producing new industrial adhesives. Different aspects of the synthesis of hybrid latexes were addressed, such us i) the use of variable content of protein; ii) the control of grafting degree between polymers, using native casein (without chemical modification) or functionalized casein, and iii) the employment of a chain transfer agent to reduce molecular weights of the acrylic polymer. The effect of the analyzed variables on the polymerization kinetics, the degree of compatibility between polymers, and the application properties of the produced latexes as adhesives were investigated.

Self-assembly in the solutions of poly(methyl methacrylates) end-capped with fluorophenyl groups

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Ekaterina R. Gasilova ◽  
Olga G. Zakharova ◽  
Sergey D. Zaitsev ◽  
Yury D. Semchikov
Keyword(s):  
Self Assembly ◽  
Chain Transfer ◽  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Selective Solvent ◽  
Photon Correlation ◽  
Molecular Weights ◽  
Methyl Methacrylates ◽  
A Chain ◽  
Strong Segregation

AbstractSelf-assembly of poly(methyl methacrylates) end-capped with -Ge(C6F5)3 groups (PMMA-F) has been studied in a selective solvent (acetone) by means of photon correlation spectroscopy and static light scattering. PMMA-F’s of different molecular weights (MW), were obtained by radical polymerization in the presence of a chain transfer agent, HGe(C6F5)3. At MW>130 000 conformational and hydrodynamic properties of PMMA-F’s is shown to be the same as of PMMA. At MW less than130 000 an aggregation starts: additional fraction of large scatterers appears in PCS. Large aggregates of Rh=200 - 300 nm are likely to be formed by bridged micellar clusters. Presence of large aggregates indicates a super strong segregation limit predicted in the work of Semenov et al.

Degradable Hydrogels for Tissue Engineering - Part II: Responses of Fibroblasts and Macrophages to Linear PHEMA

2010 ◽  
Vol 8 ◽  
pp. 91-104 ◽  
Author(s):  
Imelda Keen ◽  
Traian V. Chirila ◽  
Zeke Barnard ◽  
Z. Zainuddin ◽  
Andrew K. Whittaker
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Macrophage Cell Line ◽  
Macrophage Cell ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Murine Fibroblasts ◽  
End Groups ◽  
Linear Poly ◽  
A Chain

A series of linear poly(2-hydroxyethyl methacrylate) (PHEMA) with defined molecular weights (MW) and narrow molecular distributions were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using cumyl dithiobenzoate (CDB) as a chain transfer agent. Murine fibroblasts (3T3) were exposed to eluates from various PHEMA samples, washed or unwashed, and with or without dithioester end groups. After 72 hrs in cell culture, no cytotoxic response was elicited by the polymer samples devoid of dithioester end groups, and which also underwent a thorough washing regime. Specimens throughout the entire MW range were internalized by a macrophage (cell line Raw 264), suggesting that such polymers can be used as models for studying the biodegradation of PHEMA.

scholarly journals Removal of Trithiocarbonyl End Group of RAFT-Polymerized Poly(stearyl acrylate) and Effect of the End Group on Thermal and Structural Properties

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4169
Author(s):  
Eri Oishi ◽  
Masumi Takamura ◽  
Tatsuhiro Takahashi
Keyword(s):  
Structural Properties ◽  
Alkyl Group ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Radical Reaction ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Reversible Addition ◽  
A Chain ◽  
End Group

The effect of a long alkyl end group on the thermal and structural properties of RAFT (reversible addition-fragmentation chain transfer)-polymerized poly(stearyl acrylate) (PSA) was investigated. RAFT-polymerized PSA was prepared using 2-cyano-2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propane (CDTP) with long alkyl group as a chain transfer agent and azobisisobutyronitrile (AIBN) as an initiator. The RAFT polymerization resulted in the polymerized structure having trithiocarbonyl (TTC) at one end and isobutyronitrile at the other end. RAFT-polymerized PSA was prepared with two different molecular weights. The TTC end group was replaced by isobutyronitrile using radical reaction with AIBN through optimization of the conditions, which resulted in isobutyronitrile at both ends. The effect of the end group on the thermal and structural properties was investigated using differential scanning calorimetry and X-ray diffraction, and the results indicated that the long alkyl group from TTC lowers the melting point and semi-crystalline structure in the case of low molecular weight PSA.

scholarly journals Green TPUs from Prepolymer Mixtures Designed by Controlling the Chemical Structure of Flexible Segments

2021 ◽  
Vol 22 (14) ◽  
pp. 7438
Author(s):  
Paulina Kasprzyk ◽  
Ewa Głowińska ◽  
Paulina Parcheta-Szwindowska ◽  
Kamila Rohde ◽  
Janusz Datta
Keyword(s):  
Chemical Structure ◽  
Melt Flow Index ◽  
Molar Ratio ◽  
Flow Index ◽  
Step Method ◽  
Elongation At Break ◽  
Molecular Weights ◽  
Trimethylene Glycol ◽  
Hard Segments ◽  
A Chain

This study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols—poly(trimethylene glycol)s—with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4′-diphenylmethane diisocyanates and the bio-based 1,4-butanodiol (used as a chain extender and used to control the [NCO]/[OH] molar ratio). The impacts of the structure of flexible segments, the amount of each type of prepolymer, and the [NCO]/[OH] molar ratio on the chemical structure and selected properties of the TPUs were verified. By regulating the number of flexible segments of a given type, different selected properties of TPU materials were obtained. Thermal analysis confirmed the high thermal stability of the prepared materials and revealed that TPUs based on a higher amount of prepolymer synthesized from PO3G2700 have a tendency for cold crystallization. An increase in the amount of PO3G1000 at the flexible segments caused an increase in the tensile strength and decrease in the elongation at break. Melt flow index results demonstrated that the increase in the amount of prepolymer based on PO3G1000 resulted in TPUs favorable in terms of machining.

Synthesis and characterization of a naphthalimide–dye end-labeled copolymer by reversible addition–fragmentation chain transfer (RAFT) polymerization

2011 ◽  
Vol 89 (3) ◽  
pp. 317-325 ◽  
Author(s):  
Binxin Li ◽  
Daniel Majonis ◽  
Peng Liu ◽  
Mitchell A. Winnik
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Polymer Composition ◽  
Cooh Group ◽  
Agent Based ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Raft Agent ◽  
End Use ◽  
Naphthalimide Dye

We describe the synthesis of an end-functionalized copolymer of N-(2-hydroxypropyl)methacrylamide (HPMA) and N-hydroxysuccinimide methacrylate (NMS) by reversible addition–fragmentation chain transfer (RAFT) polymerization. To control the polymer composition, the faster reacting monomer (NMS) was added slowly to the reaction mixture beginning 30 min after initating the polymerization (ca. 16% HPMA conversion). One RAFT agent, based on azocyanopentanoic acid, introduced a –COOH group to the chain at one end. Use of a different RAFT agent containing a 4-amino-1,8-naphthalimide dye introduced a UV–vis absorbing and fluorescent group at this chain end. The polymers obtained had molecular weights of 30 000 and 20 000, respectively, and contained about 30 mol% NMS active ester groups.

scholarly journals Formation of Pharmaceutical Salts and Cocrystals via Vapour-Assisted Tumbling (VAT) – A Solvent Efficient Process with Potential Industrial Applications

2021 ◽  
Author(s):  
Alexander J. Stirk ◽  
Fabio E. S. Souza ◽  
Jenny Gerster ◽  
Fatemeh M. Mir ◽  
Avedis Karadeolian ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Environmental Impact ◽  
Industrial Applications ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
New Techniques ◽  
X Ray ◽  
Industry Standard ◽  
Pharmaceutical Salts ◽  
Solid Form

Crystallisations on both the academic and industrial scale often use large volumes of solvent. In order decrease the environmental impact of such processes, new techniques must be discovered that increase the efficiency of the solvents used. Introduced here is a process that combines repurposed industry standard hardware and aspects of mechanochemistry to produce a technique we call “Vapour Assisted Tumbling” (VAT). Pharmaceutical and well-known cocrystals and salts were formed by tumbling the coformers in an atmosphere of vaporised solvent, in this study, methanol (MeOH). This was done inside a custom built analogue of an industrial rotary cone dryer (RCD). It was found that a desired solid form could be obtained as monitored by powder X-ray diffraction and differential scanning calorimetry. By repurposing industrial RCDs, it is feasible that solid forms can be crystallised with both minimal and reusable/recyclable solvent – drastically lowering the environmental impact of such transformations.

Diethylzinc: A Chain-Transfer Agent in Intermolecular Radical Additions. A Parallel with Triethylborane

1999 ◽  
Vol 64 (25) ◽  
pp. 9189-9193 ◽  
Author(s):  
Michèle P. Bertrand ◽  
Laurence Feray ◽  
Robert Nouguier ◽  
P. Perfetti
Keyword(s):  
Chain Transfer ◽  
Chain Transfer Agent ◽  
A Chain

Rheology of Thermoplastic Polyurethanes

2007 ◽  
Author(s):  
Chang Dae Han
Keyword(s):  
Rheological Behavior ◽  
Thermoplastic Polyurethane ◽  
Complete Characterization ◽  
Chain Extender ◽  
Reaction Sequence ◽  
Molecular Weights ◽  
Soft Segments ◽  
Hard Segments ◽  
A Chain ◽  
Long Chain

Thermoplastic polyurethane (TPU) has received considerable attention from both the scientific and industrial communities (Hepburn 1982; Oertel 1985; Saunders and Frish 1962). Applications for TPUs include automotive exterior body panels, medical implants such as the artificial heart, membranes, ski boots, and flexible tubing. Figure 10.1 gives a schematic that shows the architecture of TPU, consisting of hard and soft segments. Hard segments, which form a crystalline phase at service temperature, are composed of diisocyanate and short-chain diols as a chain extender, while soft segments, which control low-temperature properties, are composed of difunctional long-chain polydiols with molecular weights ranging from 500 to 5000. The soft segments form a flexible matrix between the hard domains. TPUs are synthesized by reacting difunctional long-chain diol with diisocyanate to form a prepolymer, which is then extended by a chain extender via one of two routes: (1) by a dihydric glycol chain extender or (2) by a diamine chain extender. The most commonly used diisocyanate is 4,4’-diphenylmethane diisocyanate (MDI), which reacts with a difunctional polyol forming soft segments, such as poly(tetramethylene adipate) (PTMA) or poly(oxytetramethylene) (POTM), to produce TPU, in which 1,4-butanediol (BDO) is used as a chain extender. There are two methods widely used to produce TPU: (1) one-shot reaction sequence and (2) two-stage reaction sequence. The reaction sequences for both methods are well documented in the literature (Hepburn 1982). It should be mentioned that MDI/BDO/PTMA produces ester-based TPU. One can also produce ether-based TPU when MDI reacts with POTM using BDO as a chain extender. TPUs are often referred to as “multiblock copolymers.” In order to have a better understanding of the rheological behavior of TPUs, one must first understand the relationships between the chemical structure and the morphology; thus, a complete characterization of the materials must be conducted. The rheological behavior of TPU depends, among many factors, on (1) the composition of the soft and hard segments, (2) the lengths of the soft and hard segments and the sequence length distribution, (3) anomalous linkages (branching, cross-linking), and (4) molecular weight.

Branched polystyrenes from suspension “Strathclyde” polymerization using a vulcanization accelerator as a chain transfer agent

2019 ◽  
Vol 10 (7) ◽  
pp. 885-890 ◽  
Author(s):  
Haiyang Yong ◽  
Yongpeng Miao ◽  
Sigen A ◽  
Dong Quan ◽  
Alojz Ivankovic ◽  
...  
Keyword(s):  
Chain Transfer ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Branched Polymers ◽  
Chain Transfer Agent ◽  
Molecular Architecture ◽  
Physical Chemical ◽  
A Chain ◽  
Vulcanization Accelerator

Branched polymers exhibit a unique three-dimensional (3D) molecular architecture and distinctive physical/chemical properties, and thus have been applied in a wide variety of fields.

Research progress in materials-oriented chemical engineering in China

2019 ◽  
Vol 35 (8) ◽  
pp. 917-927 ◽  
Author(s):  
Hao Jiang ◽  
Yongsheng Han ◽  
Qiang Zhang ◽  
Jiexin Wang ◽  
Yiqun Fan ◽  
...  
Keyword(s):  
Chemical Engineering ◽  
Materials Science ◽  
Industrial Applications ◽  
Advanced Materials ◽  
Research Progress ◽  
Material Research ◽  
Engineering Science ◽  
New Materials ◽  
Engineering Development ◽  
Recent Advances

Abstract Materials-oriented chemical engineering involves the intersection of materials science and chemical engineering. Development of materials-oriented chemical engineering not only contributes to material research and industrialization techniques but also opens new avenues for chemical engineering science. This review details the major achievements of materials-oriented chemical engineering fields in China, including preparation strategies for advanced materials based on the principles of chemical engineering as well as innovative separation and reaction techniques determined by new materials. Representative industrial applications are also illustrated, highlighting recent advances in the field of materials-oriented chemical engineering technologies. In addition, we also look at the ongoing trends in materials-oriented chemical engineering in China.

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