Nondestructive testing of defects in adhesive joints

characterization of PTT/m-LLDPE blend nanocomposites at variable weight percentages of organically
modified nanoclay have been studied.
Experimental
Materials
PTT (Futura CPTT ® ) was purchased from M/s Futura Polymers Ltd., India, having density 1.3 g/cm 3 and
intrinsic viscosity 0.915 dL/g (Phenol/Carbon Tetracholride, 60/40). m-LLDPE (Relene ® ) was obtained
from M/s Reliance Industries Ltd., India having MFI 1.0 g/10 min. The clay minerals used were:
Cloisite ® 20A (C20A) Cloisite ® 30B, (C30B), obtained from M/s Southern Clay Products Inc, USA, and
Bentone ® 109 (B109) from M/s Elementis Ltd. UK. Prior to blending, PTT was dried at 110 0 C for 24
hours and all the nanoclays were dried at 80 0 C for 4 hrs.
Preparation of blend and blend nanocomposites
PTT/m-LLDPE blend of various composition (90/10, 80/20, 70/30, 50/50 by weight) were prepared using
a Torque Rheocord-9000 (HAAKE ® , Germany), at a screw speed of 70 rpm and temperature of 250 °C
for a duration of 6 minutes. m-LLDPE was added to the molten PTT after 3 minutes. The blend
composition was optimized at 70: 30 ratio of PTT : m-LLDPE. This blend composition was maintained
for preparation of polymer blend nanocomposites using various nanoclays C20A, C30B and B109 at
variable weight percent (1-5 wt. %). Specimens were prepared using mini Injection molding machine
(HAAKE ® Minijet) at 245 0 C barrel temperature, 840-870 bar injection pressure and mold temperature of
110 0 C as per ASTM standard.
X-ray Diffraction Analysis
The interlayer gallery spacing of nanoclays in the nanocomposites was studied by wide angle Philips
X’Pert MPD (Japan)X-ray diffraction at ambient temperature.
Transmission Electron Microscopy (TEM)
For TEM observation, the samples were stained with OsO4 vapor and microtomed at low temperature (-
55 0 C) and examined using a Transmission Electron Microscope (Philips CM12, The Netherlands) an
acceleration voltage of 100 kv at 100nm scale.
Mechanical Properties
Tensile & Flexural Properties were determined using Universal Testing Machine (UTM), LR-100K
(Lloyd Instruments Ltd. U.K as per ASTM-D 638 & ASTM-D 790. Izod impact strength was determined
as per ASTM D 256.
Dynamic mechanical Analysis
The dynamic mechanical analysis of was investigated using DMA242 analyzer (NETZSCH, Germany). at
fixed frequency of 1Hz, heating rate of 10K/min, under N2 atmosphere over a temperature range of -
150 o C to 200 0 C in three point bending mode.
Thermal analysis
DSC & TGA measurements were performed on a diamond DSC (Perkin Elmer Inc., USA) Pyris – 7 TGA
equipment (Perkin Elmer Inc., USA).
Results and Discussion
X-Ray diffraction analysis
The state of dispersion of the silicate layers in the blend matrix have been investigated using X-ray
diffraction patterns represented in the figure-1. The mean interlayer spacing of plane (d001) of C30B was
4.01nm.In case of the 70PTT/30m-LLDPE/5C30B hybrid, the characteristic peak shifted to a smaller
angle corresponding to d001 spacing of 4.01 nm, because of intercalation of both polymer chains into
silicate galleries [37]. A similar shifting of angles was also observed in PTT/m-LLDPE/B109 to 4.02 nm
and PTT/m-LLDPE/C20A to 4.06 0 nm nanocomposites system respectively revealing the formation of
intercalated structure. Furthermore, it was also noticed that the X-ray diffractograms in all the blend
nanocomposites system reveals diffraction peak in the similar range of 2.205 0 . However, peak intensity of