Adhesion of Elastomers, with Special Reference to Triblock Copolymers

1978 ◽  
Vol 51 (2) ◽  
pp. 354-364 ◽  
Author(s):  
A. N. Gent ◽  
G. R. Hamed
Keyword(s):  
Triblock Copolymers ◽  
Thermoplastic Elastomers ◽  
Random Copolymers ◽  
Plastic Yielding ◽  
Dissipation Process ◽  
Substrate Adhesion ◽  
Chemical Factors ◽  
Physical And Chemical ◽  
Strength Of Adhesion

Abstract Several physical and chemical factors affect the strength of adhesion (as measured by a peeling method) for elastomers adhering to rigid substrates. These factors include: the thickness of the elastomer layer (and of an adhering backing, if present); the rate of detachment and the test temperature; and the presence of chemical bonds between elastomer and the substrate. Adhesion of thermoplastic elastomers, i.e., SBS triblock copolymers, applied as hot melts, is much stronger than for the corresponding random copolymers, crosslinked in situ. These materials also show higher cohesive (tear) strength. Both effects probably arise from the same cause: an energy-dissipation process which operates at large stresses and prevents brittle fracture. This process is thought to be plastic yielding of the polystyrene domains.

scholarly journals A Quantitative Study of the Fauna of the Sandy Beach at Port Erin

1932 ◽  
Vol 18 (1) ◽  
pp. 279-296 ◽  
Author(s):  
Marjorie E. Pirrie ◽  
J. R. Bruce ◽  
H. B. Moore
Keyword(s):  
Quantitative Study ◽  
Dominant Species ◽  
Sandy Beach ◽  
Interstitial Water ◽  
Tidal Level ◽  
Isle Of Man ◽  
Chemical Factors ◽  
Physical And Chemical ◽  
Made In

A survey of the sandy beach at Port Erin, Isle of Man, was made in. September, 1931. Observations were made, at a number of stations, involving simultaneous records of the macro-fauna and its density, and certain physical and chemical factors of the sand and interstitial water, as well as tidal level on the beach. The results enable certain general conclusions to be drawn as to the causes of the observed distribution of species, and of the differences between the faunas of this and some Scottish beaches. Plans are given, indicating tidal contours, salinity, and grade composition, in situ on the beach, together with frequency diagrams for five dominant species.

scholarly journals The Evaluation of a Risk Degree for the Process of a Brown Coal Spontaneous Ignition on Dumps with Using of Modern Numeric Methods

2018 ◽  
Vol 26 (2) ◽  
pp. 71-75
Author(s):  
Petr Klouda ◽  
Vlastimil Moni ◽  
Michal Řehoř ◽  
Jan Blata ◽  
František Helebrant
Keyword(s):  
Brown Coal ◽  
Barometric Pressure ◽  
Spontaneous Ignition ◽  
Atmospheric Conditions ◽  
Database Analysis ◽  
Chemical Factors ◽  
Risk Degree ◽  
Physical And Chemical

Abstract The article is a summary of information about evaluation of a risk degree for a brown coal spontaneous ignition which is realized on the base of a database analysis of information about the development of stative quantities and desorbated gases in the stored bodies of the brown coal. The data were gained from the long term complex measurements which were realized at chosen companies during the coal mining in the previous parts of the project. In the last part of the project, we examined results of temperature models from thermographs with results of gasses and coal samples from the mines. Then, the influence of atmospheric conditions (insolation, water downfall, changes of barometric pressure etc.), the influence of coal mass degradation, the influence of physical and chemical factors, and the influence of other defective factors on the process of the coal spontaneous ignition. The gasmetry was assess with gas in-situ samples and laboratory gas models of indicative gasses for the spontaneous ignition, which were taken from the method of the thermic oxidation with the aim of the correlation finding for an epicentre of temperature within the spontaneous ignition.

scholarly journals Influence of Ecological Factors on Population Morbidity Indicators

10.12737/8227 ◽  
2015 ◽  
Vol 4 (1) ◽  
pp. 18-29
Author(s):  
Рисник ◽  
D. Risnik ◽  
Барабаш ◽  
A. Barabash ◽  
Левич ◽  
...  
Keyword(s):  
Ecological Factors ◽  
Range Limits ◽  
Environmental Standards ◽  
Normal Range ◽  
Environment Quality ◽  
Deep Well ◽  
Drinking Waters ◽  
Chemical Factors ◽  
Physical And Chemical

On the Tambov region example a research related to deep-well drinking waters’ composition influence on able-bodied population morbidity in 16 classes of diseases on the international classification has been performed. Correlation analysis, contingency tables analysis, local environmental standards calculation method (LES method) have been used for this purpose. Environment quality control in-situ-technology bases have been presented. Normal range limits of deep-well waters’ physical and chemical factors, as well as of morbidity in different classes of diseases have been calculated by means of the LES method.

scholarly journals STUDI FAKTOR FISIKA KIMIA PERAIRAN TERHADAP BIOTA AKUATIK DI EKOSISTEM SUNGAI BELAWAN

2017 ◽  
Author(s):  
Seminar Nasional Multidisiplin Ilmu 2017 ◽  
Khairul
Keyword(s):  
Laboratory Test ◽  
Aquatic Ecosystems ◽  
Ex Situ ◽  
Aquatic Biota ◽  
Average Flow ◽  
Average Flow Velocity ◽  
Chemical Factors ◽  
Average Water ◽  
Physical And Chemical

The purpose of this research is to know the condition of physical and chemical factors in aquatic biota in aquatic ecosystems against River Belawan. This research uses a method of exploration with the taking of sampling is carried out for 3 months. The taking of sampling is carried out in situ and ex situ (laboratory test). Based on the research results at the 3rd station observations can be known to the average of the highest water temperature at station 1 (29, 5 OC) and lowest in station 3 (27 OC), brightness of the highest average water at station 3 (76 cm) and the lowest in station 2 (72 cm), the average flow velocity is highest at station 1 (9.5 m/s) and the lowest in station 3 (5.3 m/s), the pH of the water the highest average at station 2 (6.8) and the lowest in station 3 (6.8), the highest average salinity at station 1 (15, 7ppt) and the lowest station 3 (5.4 ppt), DO the highest average at stations 1 and 2 (3.5 mg/litre) and lowest in station 3 (3.4 mg/liter), the highest average BOD on station 1 (6.3 mg/litre) and lowest in station 2 (0.5 mg/litre), nitrate average high at station 1 (13.1 mg/litre) and lowest in station 1 (3.9 mg/liter), and the highest average phosphate at station 3 (0.53 mg/litre) and lowest in station 1 (0.3 mg/litre).

scholarly journals Synthesis, Properties, and Biodegradability of Thermoplastic Elastomers Made from 2-Methyl-1,3-propanediol, Glutaric Acid and Lactide

Life ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 43
Author(s):  
Lamya Zahir ◽  
Takumitsu Kida ◽  
Ryo Tanaka ◽  
Yuushou Nakayama ◽  
Takeshi Shiono ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glutaric Acid ◽  
Triblock Copolymers ◽  
Tensile Tests ◽  
Thermoplastic Elastomers ◽  
Proteinase K ◽  
Synthesis Properties

An innovative type of biodegradable thermoplastic elastomers with improved mechanical properties from very common and potentially renewable sources, poly(L-lactide)-b-poly(2-methyl-1,3-propylene glutarate)-b-poly(L-lactide) (PLA-b-PMPG-b-PLA)s, has been developed for the first time. PLA-b-PMPG-b-PLAs were synthesized by polycondensation of 2-methyl-1,3-propanediol and glutaric acid and successive ring-opening polymerization of L-lactide, where PMPG is an amorphous central block with low glass transition temperature and PLA is hard semicrystalline terminal blocks. The copolymers showed glass transition temperature at lower than −40 °C and melting temperature at 130–152 °C. The tensile tests of these copolymers were also performed to evaluate their mechanical properties. The degradation of the copolymers and PMPG by enzymes proteinase K and lipase PS were investigated. Microbial biodegradation in seawater was also performed at 27 °C. The triblock copolymers and PMPG homopolymer were found to show 9–15% biodegradation within 28 days, representing their relatively high biodegradability in seawater. The macromolecular structure of the triblock copolymers of PLA and PMPG can be controlled to tune their mechanical and biodegradation properties, demonstrating their potential use in various applications.

scholarly journals Enhanced Tensile Strength of Monolithic Epoxy with Highly Dispersed TiO2-Graphene Nanocomposites

2021 ◽  
Vol 5 (7) ◽  
pp. 191
Author(s):  
Yanshuai Wang ◽  
Siyao Guo ◽  
Biqin Dong ◽  
Feng Xing
Keyword(s):  
Tensile Strength ◽  
Epoxy Resin ◽  
Mechanical Performance ◽  
Chemical Properties ◽  
High Mechanical Property ◽  
Graphene Nanocomposites ◽  
Highly Dispersed ◽  
Dispersion State ◽  
Physical And Chemical

The functionalization of graphene has been reported widely, showing special physical and chemical properties. However, due to the lack of surface functional groups, the poor dispersibility of graphene in solvents strongly limits its engineering applications. This paper develops a novel green “in-situ titania intercalation” method to prepare a highly dispersed graphene, which is enabled by the generation of the titania precursor between the layer of graphene at room temperature to yield titania-graphene nanocomposites (TiO2-RGO). The precursor of titania will produce amounts of nano titania between the graphene interlayers, which can effectively resist the interfacial van der Waals force of the interlamination in graphene for improved dispersion state. Such highly dispersed TiO2-RGO nanocomposites were used to modify epoxy resin. Surprisingly, significant enhancement of the mechanical performance of epoxy resin was observed when incorporating the titania-graphene nanocomposites, especially the improvements in tensile strength and elongation at break, with 75.54% and 176.61% increases at optimal usage compared to the pure epoxy, respectively. The approach presented herein is easy and economical for industry production, which can be potentially applied to the research of high mechanical property graphene/epoxy composite system.

Further Studies upon Chemical Factors Affecting the Breeding of Anopheles in Trinidad

1934 ◽  
Vol 25 (4) ◽  
pp. 491-494 ◽  
Author(s):  
P. A. Buxton
Keyword(s):  
Analytical Study ◽  
Chemical Constituents ◽  
Physical Factors ◽  
Factors Affecting ◽  
Early Stages ◽  
Freshwater Biology ◽  
Chemical Technique ◽  
Chemical Factors ◽  
Physical And Chemical

During the last decade, entomologists have made progress in understanding the environment in which certain insects live; in particular, we begin to understand the effect of certain physical and chemical factors, which make up a part of the environment. With this gain in knowledge, it is sometimes possible to forecast outbreaks of insects and of diseases conveyed by them, and one can sometimes say that a particular alteration of the environment will result in loss or gain. But so far as mosquitos are concerned, one must admit that though much work has been devoted to the analytical study of the water in which the early stages are passed, the results are disappointing. A consideration of the published work suggests several reasons for this. Investigation into the ecology of the mosquito has had a vogue, and much of it has been done by workers who were isolated and whose knowledge of chemical technique and freshwater biology was limited. Apart from that, the inherent difficulties are great, for the worker must hunt for the limiting chemical and physical factors among a host of others which are doubtless unimportant, and there are few clues to indicate which of the chemical constituents of the water affects the mosquito. The data are therefore voluminous and it is difficult to reduce them to order and present them so that they can be readily understood.

One-Pot Synthesis of ABC Type Triblock Copolymers via in situ Click [3 + 2] and Diels−Alder [4 + 2] Reactions

2007 ◽  
Vol 40 (2) ◽  
pp. 191-198 ◽  
Author(s):  
Hakan Durmaz ◽  
Aydan Dag ◽  
Ozcan Altintas ◽  
Tuba Erdogan ◽  
Gurkan Hizal ◽  
...  
Keyword(s):  
Triblock Copolymers ◽  
Diels Alder ◽  
One Pot ◽  
One Pot Synthesis
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