mechanically-induced chemical changes in polymeric

Polymer and REACH Regulation

A polymer is a substance and must be notified if it fulfils the criteria for classification as hazardous and it has been placed on the market Importing a polymer does not correspond to the placing on the market of the monomers and any other substance from which the polymer substance originates

What Is a Polymer?

Dec 05 2019A polymer is a chemical compound with molecules bonded together in long repeating chains Because of their structure polymers have unique properties that can be tailored for different uses Polymers are both man-made and naturally occurring Rubber for example is a natural polymeric material that has been used for thousands of years

Pattern Formation and Shape Changes in Self

We developed an efficient model for responsive gels that captures large-scale two-dimensional (2D) deformations and chemical reactions within a swollen polymer network The 2D calculations allowed us to probe not only volume changes but also changes in sample shape By focusing on gels undergoing the oscillatory Belousov-Zhabotinsky reaction we observed traveling waves of local swelling that

Numerical simulation of the impact of polymer rheology on

Polymer injectivity is an important factor for evaluating the project economics of chemical flood which is highly related to the polymer viscosity Because the flow rate varies rapidly near injectors and significantly changes the polymer viscosity due to the non-Newtonian rheological behavior the polymer viscosity near the wellbore is difficult to estimate accurately with the practical

UvA

Mechanically induced chemical and structural changes in materials Castricum H L Link to publication Citation for published version (APA): Castricum H L (2001) Mechanically induced chemical and structural changes in materials Structura n amorphous l changes polymers involv ae ra 1Se of the free energy winch becomes apparen a Ter te

[PDF] Predicting the mechanical properties of spider silk

Abstract Spider silk is attractive because it is strong and tough Moreover an enormous range of mechanical properties can be achieved with only small changes in chemical structure Our research shows that the full range of thermo-mechanical properties of silk fibres can be predicted from mean field theory for polymers in terms of chemical composition and the degree of order in the polymer

Mechanically induced luminescence changes in molecular

Home Mechanically induced luminescence changes in molecular assemblies Bretislav // Journal of Chemical Physics 2/22/2000 Vol 112 Issue 8 A memory effect has been discovered in composite films based on a polymer containing dispersed cholesteric liquid crystal which is related to the modification of the surface anchoring by an

Polymer chemistry

Polymer chemistry is a sub-discipline of chemistry that focuses on the chemical synthesis structure and chemical and physical properties of polymers and macromolecules The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry analytical chemistry and physical chemistry

Stress

(c) 1 H-NMR spectra of a mixture of MA with 50 mol% MMP before and after subjecting it to the mechanically induced oligomerization by freezing swollen PU-1 To further verify that this residue is actually produced by HABI-initiated radical polymerization we subjected PU-1 to swelling in a mixture of methyl acrylate (MA) and 50 mol% MMP

Freestanding 3D Mesostructures Functional Devices and

shape memory polymers serve as a means to achieve freestanding 3D architec-tures from the same basic approach is introduced with demonstrated ability to realize lateral dimensions characteristic feature sizes and thicknesses as small as ≈500 10 and 5 m simultaneously and the potential to scale to much larger or smaller dimensions

Chemical Aging

Aging of a polymer is the undesirable change of its chemical and physical structure during application i e mostly under atmospheric conditions Chemical changes occur during both processing and application Processing is usually carried out at elevated temperatures where thermal and oxidative reactions may become important

Guide to New Substances Fees Regulations (chemicals and

Substances not on the DSL but listed on the NDSL must still be notified but have reduced information requirements Since 1995 the NDSL has been undergoing annual revisions to reflect changes made to the TSCA Inventory five or more years before the date of the NDSL revision polymer (as defined in CEPA 1999) A substance that consists of

Mechanically Induced Multicolor Change of Luminescent

May 12 2015However fluorescent materials that undergo mechanically induced multicolor changes remain rare this Minireview is focused on such materials Topics are categorized according to the different applied forces that are required to induce the multicolor change including mechanical control of either the supramolecular structures or the chemical

Aging Plastics

Generally speaking the softer a polymer is the more flexible its polymer chains will be and the more prone it will be to time-related changes The chemical composition of the polymer the presence and concentration of oxidation-prone groups and the amount of plasticizers or additives can also have a strong effect on the process

Approaches to polymeric mechanochromic materials

When polymers are placed under mechanical stress a variety of processes may take place that range from subtle adjustments such as a reshuffling of the conformation of polymer chains to chemical reactions such as the cleavage of covalent chemical bonds to rearrangements involving multiple molecules 17-22 Taking advantage of these processes

Polypropylene Chemical Resistance Guide

Product enquiries: saleshmcpolymers 06 2012 POLYPROPYLENE CHEMICAL RESISTANCE 3/9 Technical Information By using any Technical Information contained herein you agree that said technical information is given for convenience only without any warranty or guarantee of any kind and is accepted and used at your sole risk

Mechanically induced luminescence changes in molecular

Home Mechanically induced luminescence changes in molecular assemblies Bretislav // Journal of Chemical Physics 2/22/2000 Vol 112 Issue 8 A memory effect has been discovered in composite films based on a polymer containing dispersed cholesteric liquid crystal which is related to the modification of the surface anchoring by an

UvA

Mechanically induced chemical and structural changes in materials Castricum H L Link to publication Citation for published version (APA): Castricum H L (2001) Mechanically induced chemical and structural changes in materials General rights polymer Niwa s milled together with polybutadiene (PBD) which is a highly elastic

Mechanically Induced Multicolor Change of Luminescent

May 12 2015However fluorescent materials that undergo mechanically induced multicolor changes remain rare this Minireview is focused on such materials Topics are categorized according to the different applied forces that are required to induce the multicolor change including mechanical control of either the supramolecular structures or the chemical

Stress

(c) 1 H-NMR spectra of a mixture of MA with 50 mol% MMP before and after subjecting it to the mechanically induced oligomerization by freezing swollen PU-1 To further verify that this residue is actually produced by HABI-initiated radical polymerization we subjected PU-1 to swelling in a mixture of methyl acrylate (MA) and 50 mol% MMP

Identifying mechanically induced chemical changes to

Feb 01 2018Mechano-chemical degradation whereby chain radical reactions occur that lead to the decomposition of the macromolecules is known to occur in stressed polymers Studies on mechanical induced decomposition of PE under atmospheric conditions has been shown to involve the formation of oxygen containing groups [24] [25] [26]

Polymer

A polymer (/ ˈ p ɒ l ɪ m ər / Greek poly- many + -mer part) is a substance or material consisting of very large molecules or macromolecules composed of many repeating subunits Due to their broad spectrum of properties both synthetic and natural polymers play essential and ubiquitous roles in everyday life Polymers range from familiar synthetic plastics such as polystyrene to

OSA

We report ultrafast-laser-induced photochemical structural and morphological changes in a polyimide film irradiated at the polymer-glass interface in back-incident geometry Back-illumination creates locally hot material at the interface leading to a confined photochemical change at the interface and a morphological change through a blister formation