21 results about "Dynamic mechanical analysis" patented technology

In some embodiments, the curable composition comprises: at least one high Tg alkyl (meth) acrylate, the high Tg alkyl (meth) acrylate being free of polar 5 groups and having a homopolymer Tg of at least 60 DEG C; at least one low Tg alkyl (meth) acrylate free of polar groups and having a homopolymer Tg of less than-30 DEG C; at least one crosslinking agent; and at least one photoinitiator. The curable composition is solvent-free and inkjet printable, has a viscosity of less than 25 centipoise at room temperature, and when cured to form a 100 [mu] m thick coating, has a Tg of at least 50 DEG C as measured by DMA (Dynamic Mechanical Analysis), an adhesion to glass of less than 20 g / inch (7.7 N / m) as measured by 180 DEG peel adhesion, a Young's modulus of greater than 0.5 GPa, and is optically transparent.

This invention relates to the field of tire material performance testing technology, and more particularly to a method and system for evaluating the dry grip performance of tire tread rubber based on Dynamic Mechanical Analysis (DMA). This invention performs linear baseline subtraction on the DMA tanδ-temperature curve, uses an α / α′ two-peak model for fitting, and calculates the peak area S. α S α′ And obtain the area ratio R α =S α / (S α +S α′ The results are rapidly determined based on a threshold (optimal: 0.35-0.60). The results are stable under conditions of 10Hz, 0.2%-0.3% strain, 2℃ / min, and -50 to 100℃. Compared with single-point indicators, it is more robust and transferable, and shows good consistency with actual vehicle dry braking / handling, making it suitable for rapid screening of formulations and processes.

The application discloses a kind of car-bridge pavement-bridge coupling vibration analysis methods, comprising the following steps: establishing car-bridge pavement-bridge system model, using spring damper to simulate bridge pavement layer;Establish the motion equation of rigid plate-asphalt bridge pavement layer system and export the calculation formula of stiffness coefficient K and damping coefficient C;Dynamic mechanical analysis test is carried out to asphalt mixture, its storage modulus is determined and is expressed by Prony series, the finite element simulation of rigid plate-asphalt bridge pavement layer system is carried out, and stiffness coefficient K and damping coefficient C are obtained, and the motion equation of vehicle and bridge is obtained, and the dynamic response of car-bridge pavement-bridge coupling system is obtained.The application perfects the modeling method of car-bridge coupling system in highway traffic, obtains more accurate tire road contact force and the dynamic response of car-bridge pavement-bridge coupling system, provides basis for accurately analyzing bridge pavement layer damage evolution mechanism, vehicle driving safety when passing bridge, bridge structure health monitoring and the like.

A pressure-activated adhesive article comprises a substrate and a pressure-activated adhesive layer disposed on the substrate. The pressure-activated adhesive layer is a crosslinked adhesive composition having a crosslinked siloxane polymer and at least one siloxane tackifier. The pressure-activated adhesive has a Tg of at least 50°C as measured by DMA (dynamic mechanical analysis), is non-adhesive at room temperature, but adheres to the substrate when pressure is applied to the adhesive layer.

The siloxane-based corrosion resistant adhesive is prepared from a reaction mixture such that after curing in the form of a layer, the formed siloxane-based adhesive has a stable modulus and a shear storage modulus at a frequency of 1 Hz of no more than 0.2 MPa as measured by DMA (Dynamic Mechanical Analysis). In addition, the cured siloxane-based adhesive layer is optically transparent, and after lamination to a silver nanowire film, the silver nanowire film has a change in resistance of less than 10% after aging for 500 hours at a relative humidity of 65 DEG C / 90%. The reaction mixture forming the siloxane-based adhesive includes at least one vinyl-functionalized siloxane, at least one hydrogen-functionalized siloxane, at least one hydrosilylation catalyst, at least one siloxane tackifying resin, and at least one anticorrosive agent.

A method for determining a deformation field of at least one layer of paint applied to a support during crosslinking of the layer or the layers of paint is disclosed. The method includes a step (E1) of provision of a sample, a step (E2) of 3D tomographic measurement of the sample and a set of successive steps(S) repeated iteratively comprising a step (E3) of dynamic mechanical analysis of the sample subjected to at least one temperature cycle (C), a step (E4) of 3D tomographic measurement of the sample, a step (E5) of determining a deformation field of each layer of paint of the sample.

A pressure activated adhesive article is provided that includes a substrate and a pressure activated adhesive layer disposed on the substrate. The pressure activated adhesive layer is a cross-linked adhesive composition having a cross-linked siloxane polymer and at least one siloxane tackifying resin. The pressure activated adhesive is non-tacky at room temperature, has a Tg of at least 50 DEG C as measured by DMA (Dynamic Mechanical Analysis), but adheres to the substrate upon application of pressure to the adhesive layer.

The invention discloses a material fatigue crack detection method under an electricity-heat-force coupling field. The method comprises the following steps: S1, preparing a standard sample and installing the standard sample in a dynamic mechanical analyzer with a current loading module; s2, applying an electricity-heat-force coupling field to the sample, performing a cyclic fatigue test, and monitoring damping performance parameters in real time; s3, acquiring a damping-circulation cycle diagram and a damping-strain diagram; s4, based on a damping valley value in the damping-circulation cycle diagram, judging the moment when the crack starts to rapidly expand; and S5, judging the microcrack initiation moment based on the cycle number of the maximum local damping value appearing for the first time in the damping-strain diagram. According to the method, the real-time and accurate identification of the material fatigue start rapid propagation moment and the microcrack initiation moment under the electric-thermal-mechanical coupling field is realized by utilizing the damping mutation characteristic caused by the microcrack.

A problem to be solved by the present invention is to provide a prepreg and an integrally molded article, wherein the prepreg exhibits suitable flexibility and adhesiveness, excels in formability on a complicated mold face and adhesion to a mold face, causes no positional shift, and can be efficiently reinforced and stiffened at an intended position. A main object of the present invention is to provide a prepreg including (A) reinforcing fibers, (B) a thermosetting resin, and (C) a thermoplastic resin, wherein the (C) thermoplastic resin exists in at least a part of a face of the prepreg, and wherein the prepreg satisfies the condition [I], and satisfies the condition [II] or the condition [III]: [I]: the (B) thermosetting resin has a peak in the temperature range of more than 100° C. and 180° C. or less on a loss tangent (tan δ) curve measured under isokinetic heating by dynamic mechanical analysis (DMA); [II]: on a loss angle δ curve obtained by measuring the prepreg isothermally by dynamic mechanical analysis (DMA), the loss angle δ curve has a point representing the maximum value, and has a point which represents a loss angle δ value 5° or more smaller than the maximum value, and which is on the earlier time side of the point representing the maximum value; and [III]: even if, on the loss angle δ curve obtained by measuring the prepreg isothermally by dynamic mechanical analysis (DMA), the loss angle δ curve has a point representing the maximum value, the loss angle δ curve does not have a point which represents a loss angle δ value 5° or more smaller than the maximum value, and which is on the earlier time side of the point representing the maximum value, or the loss angle δ curve does not have a point representing the maximum value, and has a descendingly behaving section in which the loss angle δ value becomes 5° or more smaller at a slope of −1.4° / minute or more.

Pressure activated adhesive articles include a substrate and a pressure activated adhesive layer disposed on the substrate. The pressure activated adhesive layer is a crosslinked adhesive composition, with a siloxane polymer that has been crosslinked, and at least one siloxane tackifying resin. The pressure activated adhesive is non-adhesive at room temperature having a Tg of at least 50° C. as measured by DMA (Dynamic Mechanical Analysis), but upon application of pressure to the adhesive layer the adhesive layer adheres to a substrate.

The embodiment of the invention provides a method, device and equipment for generating a geometric contour of a steel plate spring and a storage medium, and relates to the technical field of suspension steel plate springs. The method comprises the steps that a simulation model of the steel plate spring is generated based on design parameters of the steel plate spring, mechanical analysis is conducted on the simulation model based on a target arc height value and a time function, geometric contour data of the steel plate spring are obtained, and the geometric contour data can be used for producing the steel plate spring. According to the method, a simulation model highly matched with an actual structure is constructed through design parameter driving, mechanical analysis is carried out on the simulation model in combination with a target arc height value and a time function, simplified modeling is replaced with the simulation model, and artificial experience judgment is replaced with dynamic mechanical analysis, so that the precision of geometric contour design of the steel plate spring is remarkably improved, and the design efficiency is improved. And the dependence on artificial experience is reduced.

This invention relates to the field of rubber performance testing technology, and particularly to a method and system for rapid determination of rubber crosslinking density and segment molecular weight based on dynamic mechanical analysis. The procedure is as follows: sample drying and cutting; determining the linear viscoelastic region at 1 Hz; heating at 3 ℃ / min, isolating at a high-elasticity plateau of 90±2 ℃ and recording E′ using steady-state criteria; performing a single 5–10% large strain pretreatment or Kraus correction to subtract filler stiffness for the filled system; calculating and outputting quality control conclusions based on G′=E′ / 3, Ve=G′ / (RT), and Me=ρ / Ve. This method can be completed within 30 minutes, requires no organic solvents, and is applicable to NR, SBR, BR, EPDM and their blends. It shows good consistency with the swelling method and is suitable for rapid laboratory screening and near-line quality control in production.

In measuring dynamic viscoelasticity, a problem that a viscous fluid sample such as polymer melt index, thermosetting resin, adhesive, or paint cannot be measured for dynamic viscoelasticity can be solved. Disclosed is a sample container 1 used to measure dynamic viscoelasticity according to temperature changes occurring when heating or cooling a sample. The sample container 1 includes a lower-end-closed sample cup with an opening at an upper end, and an insertion jig 5 having a cross section smaller in area than the opening of the sample cup 2, being insertable into the sample cup 2 through the opening, and being capable of transferring vibration to a sample contained in the sample cup 2.

A patterned adhesive useful for foldable electronic display applications is provided. The patterned adhesive includes a center adhesive layer and a pair of edge adhesive layers. The pair of edge adhesive layers extends along and adjacent opposite sides of the central adhesive layer in an alternating stripe pattern. Optionally, the ratio of shear moduli between the center adhesive layer and each edge adhesive layer is from 2: 1 to 10: 1, or vice versa, measured by dynamic mechanical analysis at a frequency of 1 Hz and a temperature of 25 DEG C. Further, the center adhesive layer exhibits a difference between a refractive index of the center adhesive layer and a refractive index of the edge adhesive layer of within 0.015 as measured at a wavelength of light of 532 nm, and the center adhesive layer and the edge adhesive layer each exhibit a glass transition temperature of at most-30 DEG C.

The invention provides a fastener damping test method and device based on multi-field coupling, equipment and a medium, and relates to the technical field of rail transit, and the method comprises the steps: obtaining multi-direction strain data; performing multi-dimensional strain division and coupling construction on the multi-directional strain data according to Fourier transform to obtain a coupling analysis model; mechanical property multi-parameter association is established based on the coupling analysis model and the material mechanical parameters of the fastener, and the damping characteristics of the fastener are quantitatively fitted through the mechanical property multi-parameter association to obtain a nonlinear damping model; based on the differential scanning calorimetry model and the dynamic mechanical analysis model, association rules of the thermal performance and the damping characteristics of the fastener material are constructed, and a characteristic multi-field coupling model is obtained; and comprehensively testing the damping performance of the fastener according to the characteristic multi-field coupling model and the nonlinear damping model to obtain damping characteristic parameters of the fastener under the multi-field coupling condition. The problem that the nonlinear damping characteristic of the fastener cannot be accurately quantified is solved.

The invention relates to the technical field of tire material performance testing, in particular to a method and system for evaluating the dry ground gripping performance of tire tread rubber based on dynamic mechanical analysis (DMA). According to the method, linear baseline deduction is carried out on a DMAtan delta-temperature curve, alpha / alpha'two-peak model fitting is adopted, peak areas S alpha and S alpha 'are calculated, the area proportion R alpha = S alpha / (S alpha + S alpha') is obtained, and rapid judgment (preferably: 0.35-0.60) is carried out according to a threshold value. The result is stable under the conditions of 10Hz, 0.2%-0.3% strain, 2 DEG C / min and-50 DEG C to 100 DEG C; compared with a single-point index, the method is more stable and transplantable, has good consistency with real vehicle dry land braking / control, and is suitable for rapid screening of formulas and processes.

The present invention relates to a polyester resin, which comprises a diol repeat unit derived from a diol component; and a dicarboxylic acid repeat unit derived from a dicarboxylic acid component, wherein when a value of tan δ is measured through dynamic mechanical analysis (DMA), the temperature at the maximum value of tan δ (tan δ peak) is 100° C. or higher, and the content and composition of 1,4-cyclohexanedimethanol contained in the diol component is controlled, and to an article prepared from the polyester resin.

A waterproof member achieves waterproof properties and sound transmission properties. The waterproof member includes a waterproof membrane having a storage modulus E′ of 2.5×106 Pa or more and 7.5×106 Pa or less as measured by a dynamic mechanical analysis test in tensile mode in a frequency range of 100 to 500 Hz and satisfies at least one selected from (i) and (ii) below:(i) an initial modulus measured by a tensile test is 30 MPa or more and 100 MPa or less; and(ii) a puncture modulus measured according to a puncture strength test specified in JIS Z 1707: 2019 is 9.0 MPa or more and 40 MPa or less, the puncture modulus being calculated by dividing a maximum stress applied just before a needle penetrates the waterproof membrane by an amount of displacement of the waterproof membrane in a puncture direction at the maximum stress.

A low-viscosity adhesive composition is disclosed that achieves both impact resistance and excellent transparency. According to one aspect, an adhesive composition is provided comprising: a matrix material comprising acrylic monomers and oligomers; an initiator; and core-shell rubber particles comprising a core and a shell, wherein, according to dynamic mechanical analysis (DMA), at 25°C, a strain of 5.0%, and a frequency of 10.0 Hz, the elastic modulus of the core is ≥0.1 MPa, the shell is chemically bonded to the core, and at 25°C and 1,350 s... ‑ ¹The viscosity is below 50 cp.

- Method for determining the strain field of at least one paint layer applied to a substrate during the curing of the paint layer(s). - The determination method comprises a step (E1) of providing a sample (1), a step (E2) of 3D tomographic measurement of the sample (1), and a series of successive steps (S) repeated iteratively, including a step (E3) of dynamic mechanical analysis of the sample (1) subjected to at least one temperature cycle (C), a step (E4) of 3D tomographic measurement of the sample (1), and a step (E5) of determining the strain field of each paint layer (3) of the sample (1). Figure for the abstract: Fig. 1

A method of determining mechanical properties of a sample using thermorheological data includes providing a sample in a dynamic mechanical analysis device; selecting a temperature for the sample; performing a high-bandwidth time / frequency / temperature sweep test comprising: applying a broadband mechanical impulse over a frequency range at the temperature, and collecting thermorheological data during application of the broadband mechanical impulse; and determining mechanical properties of the sample using the thermorheological data, and, optionally, generating a viscoelastic master curve.