Nondestructive testing of defects in adhesive joints

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has been carried out using thermogravimetric analysis (TGA) by Marcilla et al [8] focusing on the degradation behavior of EVA. The thermal degradation mechanisms of poly(vinyl acetate) (PVAc) and EVA copolymers have been investigated by Rimez et al [9]. Thermal properties and flammability of EVA/LLDPE/montmorillonite nanocomposites have been studied by Chuang et al [10]. In this present investigation, an attempt has been made to study the thermal and thermo-oxidative degradation characteristics of this particular nano-silica filled blend system by thermal analysis and to correlate the thermal properties with nano- and micro-scale morphology. Experimental Materials The plastic used for the present work was LDPE - Indothene MA 400 supplied by IPCL, Vadodera, India (0.918 g/cm 3 density, MFI as per ASTM D1238 @ 190 o C using 2.16 kg load 30 g/10min melt index). The elastomer used was EVA containing 40% vinyl acetate (EVA-40) (MFI: 3) purchased from Bayer Co., Ltd. (Leverkusen, Germany). Silicon dioxide nano-powder was procured from Aldrich Chemical Co. Ltd., USA. Bis-[3-(triethoxysilyl) propyl] tetrasulphide (Si- 69) was purchased from Degussa, Germany. Sample Preparation Melt blending was carried out with EVA and LDPE with various loading of silicon dioxide nanopowder (1.5, 3 and 5 wt%, respectively) in a Brabender Plasticorder (PLE-330) at 130 0 C and 80 rpm rotor speed by varying two different sequence of additions of ingredients. The total mixing time was 10 minutes. Then they were remixed for another 2 minutes. The sheets were compression molded between two Teflon sheets for 3 minutes at 150 0 C with a pre-heat time of 1 minute and with a load of 5 Tons in an electrically heated hydraulic press to obtain films of 0.03 ~ 0.04 cm thickness. The moldings were cooled under compression to maintain the overall dimensional stability. The details of the samples and their appropriate designations are given in Table-1. Characterization Thermogravimetric measurements of the composites were conducted using TGA Q50 of TA Instruments-Waters LLC, USA operated in the dynamic mode. The conversion values 5,8,11,4,17 and 20% were used for computing the non-isothermal kinetic parameters using the Flynn-Wall- Ozawa method. For the transmission electron microscopic (TEM) observations, a high resolution transmission electron microscope (HRTEM) (JEOL JEM 2100, Japan) operated was used at an accelerating voltage of 200 kV. The bulk morphology of the blends was observed with field emission scanning electron microscope (FESEM) (Leo 1530, Carl Zeiss, Oberkochen, Germany). Results and discussion Effect of pristine nano silica filler on thermal degradation characteristics of EVA/LDPE blends under N2 atmosphere All thermograms showed two-staged decomposition (not shown here) with well defined initial and final degradation temperatures. No drastic improvement in thermal stability was observed for the filled systems. A modest improvement in thermal stability was found only in case of ELS6/4/3-2. Thus in inert atmosphere, silica particles did not have a major role to influence the thermal stability of the blend systems. 2
Effect of pristine nano silica filler on oxidative degradation characteristics of EVA/LDPE blends The control blend (EL6/4) exhibited greater thermal stability than the pure EVA and LDPE [Figure 1(a)]. Also, EVA was also found to be thermally more stable than LDPE. Thus in presence of EVA, LDPE was stabilized. In all silica filled blends there were two distinct and well separated steps in the thermogravimetric curves (TG) (corresponding weight loss peaks in derivative thermgravimetric, DTG) curves as represented in Figure 1 (b) and (c). The first step (309-315 0 C) for all samples (unfilled and filled) was possibly due to de-acetylation of vinyl acetate group of EVA with the elimination of acetic acid. As a result, double bonds were formed [10] in the main chain. The second step (413-418 0 C) might be assigned to the further degradation of polyacetylene-ethylene chains formed in the first step accompanied with the degradation of LDPE [10]. As compared to inert atmosphere, it was observed that the initial stages of degradation for all samples were accelerated in the presence of oxygen [Fig. 2(a)]. Thus the rate of reaction might be controlled by O2 diffusion in the polymeric matrix. There was also an initial gain in weight prior to deacetylation in the presence of oxygen. This suggested a rapid initial oxidation of the blends. Due to the presence of SiO2 particles, the onsets of degradation of filled blends were shifted towards higher temperatures as compared to the unfilled one. Therefore, the filled systems were thermally more stable than the pure blend. But interestingly, at very high temperature (~ above 425 0 C) the presence of nano silica accelerated degradation of filled blends. This might be due to the fact that at these temperatures silica acted as an acid catalyst. The outcomes from TGA are represented in Table 2. As compared to samples prepared following sequence-2, ELS6/4/3-1 exhibited higher thermal stability at lower temperature ranges. This indicated the occurrence of intermixing of LDPE and EVA in ELS6/4/3-1. In TEM observations also silica particles were found to be dispersed in both phases as well as in the interface for this system. Si69 increased the compatibility between two phases (in ELS6/4/3-2- Si69) and made silica well dispersed in the polymeric matrix. Hence, ELS6/4/3-1 and ELS6/4/3-2-Si69 exhibited greater thermal stability than the rest of the samples. The degradation behavior was well correlated with the morphology analyzed by TEM and FESEM. The details of the analysis are not given in this brief article. It will be mentioned during the presentation. The iso-conversional integral method named Flynn-Wall-Ozawa method suggested independently by Ozawa [11] and Flynn and Wall [12] uses Doyle’s approximation [13] of the temperature integral. From Eq. (1) and using Doyle’s approximation, the result of the integration after taking logarithms is: log β = log (AE/g (α)R) - 2.315 – 0.457 E/RT.......................(1) where β is the heating rate, A is the pre-exponential factor, E is the activation energy, α is the degree of conversion and T is the temperature. Thus, for α = constant, the plot of log β versus 1000/T obtained at several heating rates should yield a straight line whose slope can be used to evaluate the activation energy. All the filled samples showed higher activation energy of degradation than the control sample. This implied that the thermal stability of the silica filled nanocomposites was higher than the neat control blend. From plots (not shown in text) it can be observed that the best fitted straight lines (with at least 90% correlation) were nearly parallel to each other and thus confirmed the applicability of this method with in the conversion range studied. Interestingly, mean activation energy of ELS6/4/3-2 was higher than that of ELS6/4/3-1. The kinetic analysis was performed by both dynamic and static methods and the results were well correlated. However, the details of kinetic analysis will be discussed during presentation. 3
Page 1 and 2:
Design of experiments for optimizin
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Verification Experiments Confirmato
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Fig 3 Overlaid contour plots for te
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processing variables on the adhesio
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NR / CR TSC (%) 100 / 0 75 / 25 50
Page 11 and 12:
the observed high values of its T-p
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Nondestructive testing of defects i
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visible impact damage (BVID). The c
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Fig 2. Photograph of the spliced ne
Page 19 and 20:
Electrical studies on silver subsur
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temperatures exhibited by the 50 nm
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Figure 1: Variation of ln R with 1/
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Experimental Polyamide6 (PA6 with z
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Table 1: Sample code and compositio
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Blends of unsaturated polyester res
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in comparison to that of the base r
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Fig. 1 Tensile strength of rubber m
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characterization of PTT/m-LLDPE ble
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organoclay into the blend matrix re
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Figure: 5 - DSC cooling thermogram
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polypropylene exhibits β-chain sci
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ehavior. Here two possible effects
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Complex modulus (KPa) Complex visco
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has been carried out using thermogr
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Weight (%) 80 40 0 Table 1. Sample
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Mechanical properties of natural ru
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due to adsorption on rubber particl
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Preparation and Characterization of
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2.7. Fabrication of curcumin elutin
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Table 2. Effect of curcumin content
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Biodegradable nanocomposites can be
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crystallization temperature of PBAT
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Biomimetic synthesis of nanohybrids
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3.3. Thermogravimetric analysis (TG
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Fig 2: 31 P-NMR Spectra of as-synth
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In this work we have examined the c
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7. George, K.M, Alex, R, Joseph, S
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Reinforcement studies - Effect of t
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Results and Discussion Immersion an
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Stress (MPa) 26 24 22 20 18 16 14 1
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Effect of plasticizer, filler and s
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Results and Discussion Properties o
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prepolymers having higher percentag
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Table2. Formulation for Peroxide cu
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Elongation at Break The elongation
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All-PP composites based on β and
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a T E'(T) = (1) E'(T ) ref The shif
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We tried the classical WLF equation
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Figure 2. Schematic of time-tempera
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Intercalated poly (methyl methacryl
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them. The nanocomposites prepared u
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Table 1: Mechanical Properties of P
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Abstract A Review on thermally stab
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processing of different commercial
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d(%Mass)/dT ( 0 d(%Mass)/dT ( C) 0
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composites has been reported to imp
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(a) (b) Figure 2: WAXD of a) PVC/mi
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Storage Modulus (M Pa) 3000 2500 20
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17. Peprnicek, T.; Duchet, J.; Kova
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constraint of several nanometers, t
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The FT-IR spectrum .ER-Epoxy resin,
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GLASS TRANSITION TEMPERATURE (Tg) V
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AFM image of Amine containing PDMS
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8. A.Al.Abrash, F.Al.Sagheer, A.A.m
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2. Experimental Details Polypropyle
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5. Acknowlegements We would like to
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Synthesis and characterization of p
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pristine polypropylene during cooli
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a Figure 2: Typical TEM micrographs
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potassium ditelluratoargentate (III
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found to be 80.51 and 77.31, respec
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14. G. Canche-Escamilla, J.I. Cauic
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2.2. Characterization of electrospu
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eported that tortuosity decreases w
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Abstract: Effect of nano TiO2 in co
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3. Results and Discussion : The wid
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This is further evidenced from the
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Transducer using Terfenol-D/epoxy c
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esults were compared. Measurements
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500 400 300 200 100 0 Magnetostrict
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Experimental Materials Natural crum
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It is known that for alkali and alk
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Polymer sample Table1. Ion uptake b
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Abstract Protein functionalized pol
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2.4 Analysis of Particle size of ul
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Table 1 Nano particle preparation o
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As the particle size is reduced, su
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Figure- 3 SEM micrograph of EFNP of
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Excess PVA solution was drained off
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Figure 1. IR spectra of (I) PSF bas
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Photodegradable polypropylene film
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were observed as a broad peak in th
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Fig. 1. Carbonyl index variation of
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Abstract Swelling behaviour of hydr
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Swelling experiment Circular shaped
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⎛ hθ D = π⎜ ⎜ ⎝ 4Q ∞
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21. Bajsic G, Rek V. J Appl Polym S
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log (C α - C t ) 1.0 0.9 0.8 0.7 0
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esistance [2]. For converting it to
Page 200 and 201:
References 1. Bob RJ, Underwater El
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Figure-2 Insertion Loss behavior 0.
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Development of epoxy based material
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NOTATIONS USED A→E-55, AL-45.S.g-
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The Samples E, I, H and pure epoxy
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The combination B The combination I
Page 212 and 213:
Graft-copolymerization of cellulose
Page 214 and 215: Once the free-radical species (A
Page 216 and 217: References 1. Margaret I.P, Sau L.L
Page 218 and 219: Design of experiments for optimizin
Page 220 and 221: Verification Experiments Confirmato
Page 222 and 223: Fig 3 Overlaid contour plots for te
Page 224 and 225: processing variables on the adhesio
Page 226 and 227: NR / CR TSC (%) 100 / 0 75 / 25 50
Page 228 and 229: the observed high values of its T-p
Page 230 and 231: Nondestructive testing of defects i
Page 232 and 233: visible impact damage (BVID). The c
Page 234 and 235: Fig 2. Photograph of the spliced ne
Page 236 and 237: Electrical studies on silver subsur
Page 238 and 239: temperatures exhibited by the 50 nm
Page 240 and 241: Figure 1: Variation of ln R with 1/
Page 242 and 243: Experimental Polyamide6 (PA6 with z
Page 244 and 245: Table 1: Sample code and compositio
Page 246 and 247: Blends of unsaturated polyester res
Page 248 and 249: in comparison to that of the base r
Page 250 and 251: Fig. 1 Tensile strength of rubber m
Page 252 and 253: characterization of PTT/m-LLDPE ble
Page 254 and 255: organoclay into the blend matrix re
Page 256 and 257: Figure: 5 - DSC cooling thermogram
Page 258 and 259: polypropylene exhibits β-chain sci
Page 260 and 261: ehavior. Here two possible effects
Page 262 and 263: Complex modulus (KPa) Complex visco
Page 266 and 267: Weight (%) 80 40 0 Table 1. Sample
Page 268 and 269: Mechanical properties of natural ru
Page 270 and 271: due to adsorption on rubber particl
Page 272 and 273: Preparation and Characterization of
Page 274 and 275: 2.7. Fabrication of curcumin elutin
Page 276 and 277: Table 2. Effect of curcumin content
Page 278 and 279: Biodegradable nanocomposites can be
Page 280 and 281: crystallization temperature of PBAT
Page 282 and 283: Biomimetic synthesis of nanohybrids
Page 284 and 285: 3.3. Thermogravimetric analysis (TG
Page 286 and 287: Fig 2: 31 P-NMR Spectra of as-synth
Page 288 and 289: In this work we have examined the c
Page 290 and 291: 7. George, K.M, Alex, R, Joseph, S
Page 292 and 293: Reinforcement studies - Effect of t
Page 294 and 295: Results and Discussion Immersion an
Page 296 and 297: Stress (MPa) 26 24 22 20 18 16 14 1
Page 298 and 299: Effect of plasticizer, filler and s
Page 300: Results and Discussion Properties o
Page 303 and 304: prepolymers having higher percentag
Page 305 and 306: Table2. Formulation for Peroxide cu
Page 307 and 308: Elongation at Break The elongation
Page 309 and 310: All-PP composites based on β and
Page 311 and 312: a T E'(T) = (1) E'(T ) ref The shif
Page 313 and 314: We tried the classical WLF equation
Page 315 and 316:
Figure 2. Schematic of time-tempera
Page 317 and 318:
Intercalated poly (methyl methacryl
Page 319 and 320:
them. The nanocomposites prepared u
Page 321 and 322:
Table 1: Mechanical Properties of P
Page 323 and 324:
Abstract A Review on thermally stab
Page 325 and 326:
processing of different commercial
Page 327 and 328:
d(%Mass)/dT ( 0 d(%Mass)/dT ( C) 0
Page 329 and 330:
composites has been reported to imp
Page 331 and 332:
(a) (b) Figure 2: WAXD of a) PVC/mi
Page 333 and 334:
Storage Modulus (M Pa) 3000 2500 20
Page 335 and 336:
17. Peprnicek, T.; Duchet, J.; Kova
Page 337 and 338:
constraint of several nanometers, t
Page 339 and 340:
The FT-IR spectrum .ER-Epoxy resin,
Page 341 and 342:
GLASS TRANSITION TEMPERATURE (Tg) V
Page 343 and 344:
AFM image of Amine containing PDMS
Page 345 and 346:
8. A.Al.Abrash, F.Al.Sagheer, A.A.m
Page 347 and 348:
2. Experimental Details Polypropyle
Page 349 and 350:
5. Acknowlegements We would like to
Page 351 and 352:
Synthesis and characterization of p
Page 353 and 354:
pristine polypropylene during cooli
Page 355 and 356:
a Figure 2: Typical TEM micrographs
Page 357 and 358:
potassium ditelluratoargentate (III
Page 359 and 360:
found to be 80.51 and 77.31, respec
Page 361 and 362:
14. G. Canche-Escamilla, J.I. Cauic
Page 363 and 364:
2.2. Characterization of electrospu
Page 365 and 366:
eported that tortuosity decreases w
Page 367 and 368:
Abstract: Effect of nano TiO2 in co
Page 369 and 370:
3. Results and Discussion : The wid
Page 371 and 372:
This is further evidenced from the
Page 373 and 374:
Transducer using Terfenol-D/epoxy c
Page 375 and 376:
esults were compared. Measurements
Page 377 and 378:
500 400 300 200 100 0 Magnetostrict
Page 379 and 380:
Experimental Materials Natural crum
Page 381 and 382:
It is known that for alkali and alk
Page 383 and 384:
Polymer sample Table1. Ion uptake b
Page 385 and 386:
Abstract Protein functionalized pol
Page 387 and 388:
2.4 Analysis of Particle size of ul
Page 389 and 390:
Table 1 Nano particle preparation o
Page 391 and 392:
As the particle size is reduced, su
Page 393 and 394:
Figure- 3 SEM micrograph of EFNP of
Page 395 and 396:
Excess PVA solution was drained off
Page 397 and 398:
Figure 1. IR spectra of (I) PSF bas
Page 399 and 400:
Photodegradable polypropylene film
Page 401 and 402:
were observed as a broad peak in th
Page 403 and 404:
Fig. 1. Carbonyl index variation of
Page 405 and 406:
Abstract Swelling behaviour of hydr
Page 407 and 408:
Swelling experiment Circular shaped
Page 409 and 410:
⎛ hθ D = π⎜ ⎜ ⎝ 4Q ∞
Page 411 and 412:
21. Bajsic G, Rek V. J Appl Polym S
Page 413 and 414:
log (C α - C t ) 1.0 0.9 0.8 0.7 0
Page 415 and 416:
esistance [2]. For converting it to
Page 417 and 418:
References 1. Bob RJ, Underwater El
Page 419 and 420:
Figure-2 Insertion Loss behavior 0.
Page 421 and 422:
Development of epoxy based material
Page 423 and 424:
NOTATIONS USED A→E-55, AL-45.S.g-
Page 425 and 426:
The Samples E, I, H and pure epoxy
Page 427 and 428:
The combination B The combination I
Page 429 and 430:
Graft-copolymerization of cellulose
Page 431 and 432:
Once the free-radical species (A
Page 433 and 434:
References 1. Margaret I.P, Sau L.L
Page 435 and 436:
Studies on processing of styrene bu
Page 437 and 438:
3 Results 4. Swelling index - Tolue
Page 439:
4. Swelling index The swelling indi
Page 442 and 443:
Effect of post drawing parameters o
Page 444 and 445:
Drawing the fiber at 100 0 C, which
Page 446 and 447:
Table 1: Experimental details of va
Page 448 and 449:
and the primary variables in the go
Page 450 and 451:
The equ (3.2) is linearized and we
Page 452 and 453:
Initial Deformed coordinates coordi
Page 454 and 455:
As 'C' channel structures is non-sy
Page 456 and 457:
Figure 3: Von-mises stress distribu
Page 458 and 459:
Synthesis, curing and characterizat
Page 460 and 461:
Results and Discussion: . Table 4.1
Page 462 and 463:
TGDDM/DDM SYSTEM: There are 2 trans
Page 464 and 465:
Table 4.6: DSC Results DSC thermo g
Page 466 and 467:
CONCLUSION: 1. Tetraglycidyl Diamin
Page 468 and 469:
Studies on processing of styrene bu
Page 470 and 471:
3 Results 4. Swelling index - Tolue
Page 472:
4. Swelling index The swelling indi
Page 475 and 476:
Effect of post drawing parameters o
Page 477 and 478:
Drawing the fiber at 100 0 C, which
Page 479 and 480:
Table 1: Experimental details of va
Page 481 and 482:
and the primary variables in the go
Page 483 and 484:
The equ (3.2) is linearized and we
Page 485 and 486:
Initial Deformed coordinates coordi
Page 487 and 488:
As 'C' channel structures is non-sy
Page 489 and 490:
Figure 3: Von-mises stress distribu
Page 491 and 492:
Synthesis, curing and characterizat
Page 493 and 494:
Results and Discussion: . Table 4.1
Page 495 and 496:
TGDDM/DDM SYSTEM: There are 2 trans
Page 497 and 498:
Table 4.6: DSC Results DSC thermo g
Page 499 and 500:
CONCLUSION: 1. Tetraglycidyl Diamin
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Nondestructive testing of defects in adhesive joints

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