The chemical structure dependence of interaction strength between polymers and mobility of polymer chains in the polymer interface

1997 ◽  
Vol 7 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Shigeru Yao ◽  
Eiichi Kamei ◽  
Takayoshi Matsumoto
Keyword(s):  
Chemical Structure ◽  
Interaction Strength ◽  
Polymer Chains ◽  
Structure Dependence ◽  
Polymer Interface

scholarly journals Assemblies of conjugated polymers: Intermolecular and intramolecular effects on the photophysical properties of conjugated polymers

2002 ◽  
Vol 74 (11) ◽  
pp. 2031-2044 ◽  
Author(s):  
Jinsang Kim
Keyword(s):  
Solid State ◽  
Conjugated Polymers ◽  
Conjugated Polymer ◽  
Chemical Structure ◽  
Field Effect Transistors ◽  
Photophysical Properties ◽  
Polymer Chains ◽  
Critical Parameters ◽  
Light Emitting ◽  
Recent Developments

Conjugated polymers are emerging materials for electronic applications due to the tunability of their properties through variation of their chemical structure. Their applications, which currently include light-emitting diodes (LEDs), field effect transistors (FETs), plastic lasers, batteries, and sensors, are expanding to many new areas. The two critical parameters that determine the function of conjugated polymer-based devices are chemical structure and nanostructure of a conjugated polymer in the solid state. While the physical properties of isolated polymers are primarily controlled by their chemical structure, these properties are drastically altered in the solid state due to electronic coupling between polymer chains as determined by their interpolymer packing and conformation. However, the development of effective and precise methods for controlling the nanostructure of polymers in the solid state has been limited because polymers often fail to assemble into organized structures due to their amorphous character and large molecular weight.In this review, recent developments of organizing methods of conjugated polymers and the conformation and interpolymer interaction effects on the photophysical properties of conjugated polymers are summarized.

Controlled and Living Polymerizations Induced with Rhodium Catalysts. A Review

2003 ◽  
Vol 68 (10) ◽  
pp. 1745-1790 ◽  
Author(s):  
Jan Sedláček ◽  
Jiří Vohlídal
Keyword(s):  
Molecular Weight ◽  
Ionic Liquids ◽  
Weight Distribution ◽  
Chemical Structure ◽  
Reaction Medium ◽  
Polymer Chains ◽  
Rhodium Catalysts ◽  
High Tolerance ◽  
Polymer Molecules ◽  
Living Polymerizations

In the last fifteen years, a large variety of specialty polymers of diverse chemical structure and functionality have been synthesized with the rhodium-based catalysts. The high tolerance to the reaction medium and functional groups of monomers, as well as ability to control various structure features of the polymer formed are typical properties of these catalysts. In addition, some rhodium catalysts can be anchored to inorganic or organic supports or dissolved in ionic liquids to form heterophase polymerization systems, which opens the way to pure, well-defined polymers free of the catalyst residues, as well as to recycling rhodium catalysts. This review provides a survey on the polymerization reactions induced with rhodium-based catalysts, in which one or more structure attributes of the polymer formed are subject to control. The structure attributes considered are (i) sequential arrangement of monomeric units along polymer chains; (ii) head-tail isomerism of polymer molecules; (iii) configurational structure of polymer molecules; (iv) conformation of polymer molecules; and (v) molecular weight and molecular-weight distribution of the polymer formed. A review with 188 references.

The strength of highly elastic materials

1967 ◽  
Vol 300 (1460) ◽  
pp. 108-119 ◽  
Keyword(s):  
Chemical Structure ◽  
Unit Area ◽  
Strength Properties ◽  
Polymer Chains ◽  
Chemical Bonds ◽  
Elastic Materials ◽  
Chemical Corrosion ◽  
Vulcanized Rubber ◽  
Theory And Experiment ◽  
Highly Elastic Materials

Under repeated stressing, cracks in a specimen of vulcanized rubber may propagate and lead to failure. It has been found, however, that below a critical severity of strain no propagation occurs in the absence of chemical corrosion. This severity defines a fatigue limit for repeated stressing below which the life can be virtually indefinite. It can be expressed as the energy per unit area required to produce new surface ( T 0 ), and is about 5 x 10 4 erg/cm 2 . In contrast with gross strength properties such as tear and tensile strength, T 0 does not correlate with the viscoelastic behaviour of the material and varies only relatively slightly with chemical structure. It is shown that T 0 can be calculated approximately by considering the energy required to rupture the polymer chains lying across the path of the crack. This energy is calculated from the strengths of the chemical bonds, secondary forces being ignored. Theory and experiment agree within a factor of 2. Reasons why T 0 and the gross strength properties are influenced by different aspects of the structure of the material are discussed.

New Polymeric Binders in Ceramic Processing

2006 ◽  
Vol 45 ◽  
pp. 453-461 ◽  
Author(s):  
Mikolaj Szafran ◽  
Gabriel Rokicki
Keyword(s):  
Chemical Structure ◽  
Ceramic Powder ◽  
Tape Casting ◽  
Water Soluble ◽  
Polymer Chains ◽  
Allyl Ether ◽  
Hydroxyl Groups ◽  
Alumina Ceramics ◽  
Water Dispersible ◽  
Polymeric Binders

The results of studies on the application of new water-dispersible binders such as poly(acrylic-styrene), poly(acrylic-allyl ether) for die and isostatic pressing and tape casting of Al2O3 ceramics are presented. The properties of these acrylic polymers were modified by insertion of selected amphiphilic macromonomers into the polymer chains. These amphiphilic macromonomers, due to the proper ratio of the hydrophilic to hydrophobic fragments, play the role of not only an internal plasticizer, but they also modify the adhesion of such binders to the ceramic powder particles. The influence of chemical structure of these copolymers on the properties of alumina ceramics is discussed. The investigations on properties of alumina ceramics obtained by gelcasting method using new water soluble acrylic monomers containing hydroxyl groups in their chemical structure as well as by direct coagulation casting method using polymeric flocculants are also presented and discussed.

Chemical Structure Dependence of Surface Layer Thickness on Polymer Films

2020 ◽  
Vol 124 (23) ◽  
pp. 12448-12456
Author(s):  
Cuiyun Zhang ◽  
Li Li ◽  
Junren Chen ◽  
Yuhui Yang ◽  
Biao Zuo ◽  
...  
Keyword(s):  
Surface Layer ◽  
Layer Thickness ◽  
Polymer Films ◽  
Chemical Structure ◽  
Structure Dependence ◽  
Surface Layer Thickness

Mathematical Modelling of Urea-Formaldehyde Polymerization Kinetics Using Mechanism Approach

2013 ◽  
Vol 701 ◽  
pp. 337-341
Author(s):  
Polphat Ruamcharoen ◽  
Jareerat Ruamcharoen
Keyword(s):  
Kinetic Model ◽  
Chemical Structure ◽  
Kinetic Modelling ◽  
Urea Formaldehyde ◽  
Polymer Chains ◽  
Polymerization Process ◽  
Formaldehyde Resin ◽  
Formaldehyde Concentration ◽  
Reactive Polymer ◽  
Good Agreement

Nowadays, formaldehyde is considered to be a hazardous volatile chemical. One of the formaldehyde sources is urea-formaldehyde resin which is mainly used as an adhesive in particleboard production. Hence, it is necessary to minimize the formaldehyde residue from urea-formaldehyde synthesis. This present work involves the kinetic modelling of urea-formaldehyde polymerization to predict formaldehyde concentration during the pre-polymerization process. On the basis of previous proposed mechanism, the kinetic model which accounted for the number of the functional groups on urea and formaldehyde and also reactive polymer chains was developed as a set of ordinary differential equations (ODEs). The formaldehyde concentrations from computer simulation results were compared with those from experimental investigation. Good agreement between simulation and experimental results was obtained. The developed kinetic model can be also applied to predict the functional group evolution during polymerization. This helps producers select the condition for production to minimize formaldehyde residue and predict the chemical structure of final product.

scholarly journals Polyphenylsulfone (PPSU)-Based Copolymeric Membranes: Effects of Chemical Structure and Content on Gas Permeation and Separation

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2745
Author(s):  
Fan Feng ◽  
Can-Zeng Liang ◽  
Ji Wu ◽  
Martin Weber ◽  
Christian Maletzko ◽  
...  
Keyword(s):  
Free Volume ◽  
Gas Separation ◽  
Chemical Structure ◽  
Gas Permeability ◽  
Life Time ◽  
Gas Permeation ◽  
Polymer Chains ◽  
Polymer Materials ◽  
Fractional Free Volume ◽  
Trade Off

Although various polymer membrane materials have been applied to gas separation, there is a trade-off relationship between permeability and selectivity, limiting their wider applications. In this paper, the relationship between the gas permeation behavior of polyphenylsulfone(PPSU)-based materials and their chemical structure for gas separation has been systematically investigated. A PPSU homopolymer and three kinds of 3,3′,5,5′-tetramethyl-4,4′-biphenol (TMBP)-based polyphenylsulfone (TMPPSf) copolymers were synthesized by controlling the TMBP content. As the TMPPSf content increases, the inter-molecular chain distance (or d-spacing value) increases. Data from positron annihilation life-time spectroscopy (PALS) indicate the copolymer with a higher TMPPSf content has a larger fractional free volume (FFV). The logarithm of their O2, N2, CO2, and CH4 permeability was found to increase linearly with an increase in TMPPSf content but decrease linearly with increasing 1/FFV. The enhanced permeability results from the increases in both sorption coefficient and gas diffusivity of copolymers. Interestingly, the gas permeability increases while the selectivity stays stable due to the presence of methyl groups in TMPPSf, which not only increases the free volume but also rigidifies the polymer chains. This study may provide a new strategy to break the trade-off law and increase the permeability of polymer materials largely.

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