The Nature and Action of Tackifier Resins

1988 ◽  
Vol 61 (3) ◽  
pp. 448-469 ◽  
Author(s):  
Derek W. Aubrey
Keyword(s):  
Phase Separation ◽  
Surface Energy ◽  
Response Times ◽  
Viscoelastic Behavior ◽  
High Energy ◽  
Phase Morphology ◽  
Two Phase ◽  
Chemical Structures ◽  
Separation Force ◽  
High Degree

Abstract A good tackifler resin appears to require a combination of high T9 at low molecular weight, and for this a highly condensed alicyclic structure appears to be desirable. Except for the rosin derivatives, the chemical structures of common tackifier resins are not fully resolved and some more definitive studies are needed. In addition, a high degree of miscibility of resin with rubber is important. Although some common tackifier resins cause phase separation over certain concentration ranges when blended with rubbers, this is probably exceptional, and it seems likely that most adhesive compositions are single phase in this respect. Where phase separation does occur, there is a need for fuller elucidation of the phase morphology and composition of the phases. The widely-held view that a two-phase morphology is necessary for the development of high tack appears to be incorrect. The few studies which have been carried out so far indicate that the surface energy of a rubber is modified only slightly by the incorporation of a tackifier resin. It is unlikely that this surface energy change can seriously affect the tack value as measured by the common form of probe test. The viscoelastic behavior of rubber-resin blends provides an adequate explanation for the phenomenon of tack. Over long response times, the low modulus (high compliance) of the blend compared with that of the rubber alone allows a high degree of intermolecular contact to be achieved during the bonding stage of a tack test. Over short response times, corresponding to the de-bonding stage of the test, the blend shows transition zone response with high energy dissipation and consequent high separation force. For further progress in our understanding, however, there is a need to distinguish clearly between the bonding and debonding effects of the resin and also for a more definitive study of the factors controlling the bonding stage.

Two-Phase Microstructures Formed by Phase-Separation of Coherent Precipitates in Elastically Constrained Alloy Systems

2010 ◽  
Vol 638-642 ◽  
pp. 2215-2220 ◽  
Author(s):  
Minoru Doi
Keyword(s):  
Free Energy ◽  
Phase Separation ◽  
Surface Energy ◽  
Phase Region ◽  
Precipitate Phase ◽  
Two Phase ◽  
Phase Separations ◽  
Chemical Free Energy ◽  
Elastic Constraint ◽  
Alloy Systems

Coherent two-phase microstructures consisting of ordered precipitate and disordered matrix phases sometimes exhibit a phase-separation, which brings the split and/or the decelerated coarsening of precipitates. When the coherent two-phase microstructure of A1+L12 (+’) in Ni-base alloys are aged inside the two-phase region of A1+L12 , the L12 precipitate sometimes exhibit a phase-separation and A1 phase newly appears and grows in each L12 precipitate. Phase-separations of the same type to the above also take place due to ageing of coherent two-phase microstructures of A2+D03 and A2+B2 in Fe-base alloys: D03 and B2 precipitates sometimes exhibit phase-separations and A2 phase newly appears and grows in both precipitates. These types of phase-separation take place under the influence of chemical free energy. In the course of further ageing, the new disordered phases of A1 and A2 change their morphology in various ways depending on the elastic constraint: i.e. the morphology of new A1 or A2 phase is influenced by the elastic energies and the surface energy.

scholarly journals Residual Stress Evolution during Decomposition of Ti(1-x)Al(x)N Coatings Using High-Energy X-Rays

2006 ◽  
Vol 524-525 ◽  
pp. 619-624 ◽  
Author(s):  
Mark R. Terner ◽  
Peter Hedström ◽  
Jonathan Almer ◽  
J. Ilavsky ◽  
Magnus Odén
Keyword(s):  
Residual Stress ◽  
Phase Separation ◽  
Elevated Temperatures ◽  
High Energy ◽  
Film Plane ◽  
X Rays ◽  
X Ray Diffraction ◽  
Synchrotron Source ◽  
Simultaneous Acquisition ◽  
Initial Stage

Residual stresses and microstructural changes during phase separation in Ti33Al67N coatings were examined using microfocused high energy x-rays from a synchrotron source. The transmission geometry allowed simultaneous acquisition of x-ray diffraction data over 360° and revealed that the decomposition at elevated temperatures occurred anisotropically, initiating preferentially along the film plane. The as-deposited compressive residual stress in the film plane first relaxed with annealing, before dramatically increasing concurrently with the initial stage of phase separation where metastable, nm-scale c-AlN platelets precipitated along the film direction. These findings were further supported from SAXS analyses.

scholarly journals Automated Computation of One-Loop Amplitudes

2018 ◽  
Vol 68 (1) ◽  
pp. 291-312 ◽  
Author(s):  
Celine Degrande ◽  
Valentin Hirschi ◽  
Olivier Mattelaer
Keyword(s):  
High Energy Physics ◽  
Expert Knowledge ◽  
Hadron Collider ◽  
High Energy ◽  
Hadron Colliders ◽  
Collider Phenomenology ◽  
Physics Community ◽  
High Degree ◽  
Energy Physics ◽  
Loop Amplitudes

The automation of one-loop amplitudes plays a key role in addressing several computational challenges for hadron collider phenomenology: They are needed for simulations including next-to-leading-order corrections, which can be large at hadron colliders. They also allow the exact computation of loop-induced processes. A high degree of automation has now been achieved in public codes that do not require expert knowledge and can be widely used in the high-energy physics community. In this article, we review many of the methods and tools used for the different steps of automated one-loop amplitude calculations: renormalization of the Lagrangian, derivation and evaluation of the amplitude, its decomposition onto a basis of scalar integrals and their subsequent evaluation, as well as computation of the rational terms.

efficiency. By measurements of total odour strength in a treatment plant the ED values pointed out the sludge press and dewatering process as the predominant odour sources of the plant. In the venting air from this position extremely high ED values were recorded. This air was led through a carbon filter for odour reduction. Olfactometric measurements at the filter revealed poor odour reducing efficiency. It was observed that odour compounds were not destroyed in the filter. They only restrained until the carbon became saturated, and thereafter evaporated into the outlet air contributing to the odour strength. The filter capacity was obviously too small for the heavy load. Attempts to reduce the odour strength before the filter did not succeed, until the air was led through a container filled with saturated lime slurry (pH = 12-14). The slurry was part of a precipitation process in the plant. Dispersion in the alkaline slurry extensively reduced the odour strength of the air, resulting in sufficient capacity of the carbon filter also when handling heavy loads of sewage sludge. Since then the carbon filter has worked well, within the limitation of such filters in general. Neither is it observed signs indicating reduced precipitation properties of the lime slurry. Measurements of total odour strength in combustion processes imply sampling challenges. Beside the chemical scrubber process, combustion of odorous air is the best odour reducing method. The disadvantage of this process is the high energy costs. Treatment at apropriate conditions, however, will destroy the odorous compounds extensively. Temperatures about 850 C and contact time up to 3 seconds are reported (2,3). Olfactometric measurements in combustion processes involve certain sampling problems caused by the temperature difference between inlet and outlet. The humidity of outlet air must also be taken into consideration. Problems may occur when hot outlet air is sampled at low temperatures. In most such cases sampling is impossible without special arrangements. Such conditions are present during odour measurements in fish meal plants with combustion as the odour reducing method. The largest problem turned out to be the temperature differences between outlet air (85-220 C) and outdoor temperatures (0-15 C), causing condensation. The dew point of the outlet air was calculated, and experiments were carried out with dilution of the outlet air to prevent condensation in the sampling bags. Condensation was prevented by diluting the outlet air 5-150 times with dry, purified N gas. Comparison of N -diluted and undiluted samples revealed large differences in ED value. In samples demanding a high degree of dilution to prevent condensation, the measured odour strength was up to 5 times higher than in the undiluted corresponding samples. Samples demanding less dilution showed less deviating results. 4. CONCLUSIONS In the attempt to minimize odour emission, olfactometric measurements of total odour strength give useful informations about the odour reducing efficiency of different processes as a function of parameters like dosage of chemicals in scrubbers, humidity and temperature in packed filters, flow rates, etc. Olfactometric measurements also point out the main odour sources of the plant. From a set of olfactometric data combined with other essential

1986 ◽  
pp. 98-98
Keyword(s):  
Treatment Plant ◽  
High Energy ◽  
Dew Point ◽  
Precipitation Process ◽  
Heavy Load ◽  
Heavy Loads ◽  
Combustion Processes ◽  
Sampling Problems ◽  
High Degree ◽  
Carbon Filter

scholarly journals Studying the Influence of Mica Particle Size on the Properties of Epoxy Acrylate/Mica Composite Coatings through Reducing Mica Particle Size by the Ball-Milled Method

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 98
Author(s):  
Yaling Da ◽  
Jianxing Liu ◽  
Zixian Gao ◽  
Xiangxin Xue
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Composite Coatings ◽  
High Energy ◽  
Particle Sizes ◽  
Epoxy Acrylate ◽  
Pencil Hardness ◽  
Uv Curable ◽  
Chemical Structures ◽  
Mica Composite

In this work, a series of epoxy acrylate (EA)/mica composite coatings were synthesized through introducing mica powders of different particle size into epoxy acrylate coatings and using an ultraviolet (UV) curing technique to investigate the influence of mica particle size on the coatings. Mica powders of different particle sizes were obtained by ball-milling for 4, 8, 12, 16, and 20 h with a planetary high-energy ball mill. The particle size and morphologies of ball-milled mica powders were characterized by laser particle size analyzer and scanning electron microscopy (SEM). The results indicated that planetary ball-milling reduced the particle size of mica powders effectively. Mica powders that were un-ball-milled and ball-milled were added into the epoxy acrylate matrix by a blending method to synthesize the organic-inorganic UV curable coatings. The optical photographs of the coatings showed greater stability of liquid mixtures with smaller particle size fillers. The chemical structures of EA/mica composite coatings were investigated by Fourier transform infrared spectroscopy (FTIR), and the conversion rate of C=C bonds was calculated. The results indicated that the C=C conversion of coatings with mica powders of smaller particle sizes was higher. Tests of mechanical properties and tests using electrochemical impedance spectroscopy (EIS) showed that pencil hardness, impact resistance, and coating resistance were improved due to the reduction of mica powders particle size.

Microhardness Enhancement in Fully Dense Fe-Based Nanophase Metallic Alloys

1995 ◽  
Vol 400 ◽  
Author(s):  
L. He ◽  
E. Ma
Keyword(s):  
Grain Size ◽  
High Energy ◽  
Metallic Alloys ◽  
Full Density ◽  
Strengthening Effect ◽  
Two Phase ◽  
Grain Sizes ◽  
Sinter Forging ◽  
Interphase Boundaries ◽  
Energy Ball

AbstractNano-grained Fe-29Al-2Cr intermetallic and Fe-Cu two-phase composites have been consolidated to full density from powders produced by high-energy ball milling, using a sinter forging procedure developed recently in our laboratory. Grain sizes remained within nanophase range (<100 nm) after consolidation. Microhardness tests of Fe-29Al-2Cr samples consolidated to different density levels indicate a significant strengthening effect due to nanoscale grain size and a monotonic microhardness increase with decreasing residual porosity. Fully dense Fe-Cu composites exhibit enhanced microhardness as compared with rule-of-mixtures predictions, which may be attributable to interface strengthening at fcc-bcc interphase boundaries.

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