Study of the Water Uptake and Internal Defects of Jute-Reinforced Polymer Composites with a Digital Neutron Radiography Technique M. K. Alam, 1 Mubarak A. Khan, 1 E. H. Lehmann, 2 P. Vontobel 2 1 Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, P.O. Box 3787, Dhaka 1000, Bangladesh 2 Spallation Neutron Source Division, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland Received 22 February 2006; accepted 20 November 2006 DOI 10.1002/app.26358 Published online 1 May 2007 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: The water-uptake behavior of jute fabric and its composites with polycarbonate and polypropylene was monitor by a digital neutron radiography technique. The thermal neutron radiography facility of neutron trans- mission radiography (NEUTRA) at spallation source (SINQ) of the Paul Scherrer Institute was used for this work. The internal defects, such as voids, cracks, and inhomogeneity, of the composites were studied. The water-uptake behav- ior of the jute fiber was also studied with a digital neutron radiography technique. The natural jute fiber showed higher water absorption than the composites. No voids or inclusions in these composites were observed. Moreover, both the jute and polymer were uniformly distributed and well mixed with the polymer matrix. Ó 2007 Wiley Periodi- cals, Inc. J Appl Polym Sci 105: 1958–1963, 2007 Key words: adsorption; reinforcement; composite INTRODUCTION The Paul Scherrer Institute operates the strongest continuously running spallation neutron source (SINQ). 1 The main features and properties of the facility were described by Lehmann and Pleinert. 2 The thermal neutron radiography facility NEUTRA 3 has been designed with a large diameter at the exit of the neutron flight tube (40 cm), which allows the inspection of large objects from industry and all other sectors. Usually, the option for neutron radiog- raphy inspection is chosen in cases for which X-ray or other nondestructive testing methods have failed. The utilization of a charge-coupled device (CCD) camera has other advantages, such as a low acquisi- tion time, high frame rates, reproducibility, and a high dynamic range. This detector is applied to investigations of time-dependent processes, distribu- tion analysis, and quantitative studies. 4 One of the main features of this method is the direct availability of the investigated results in a digitized form as ma- trix P(x,y). Each value of P(x i ,y j ) corresponds to the time- and energy-averaged reaction rate in the pri- mary detector induced by the incident radiation. Some important properties of this method are intro- duced in ref. 5. Many complex structures, such as tubes, car doors, interior paneling, and sandwich plates, are made of composites. 6 The radiography station is installed inside a con- crete bunker guaranteeing satisfactory shielding con- ditions and adequate space for the detector and sam- ple positioning. The spallation neutron source (SINQ) possesses some important advantageous properties, such as a low g background, a large beam size (100–400 cm 2 ) and very flat beam profile, a high length/diameter ratio, a reasonable neutron flux level 5 (3  10 6 cm 2 s 1 ), good linearity, and good reproducibility, which are very useful for its future utilization. The characteristics of the NEUTRA facility are described in ref. 7. SINQ is driven by a 590-MeV proton beam 1 gener- ated by a cyclotron with a beam current of about 850 mA. To obtain a 16-bit conventional radiographic image, one has to integrate the scintillator light on the CCD chip. The exact exposure time, of course, is determined by the sample thickness, the sample materials, and the neutron flux provided from the source. Additionally, the readout time, depending on the dynamic range and the pixel number of the CCD, puts a lower limit on the highest reachable frame rate. 8 Because of increasing environmental conscious- ness and the demands of traditional composite structures, which are usually made of glass, carbon, or aramid fibers embedded in epoxy, unsaturated polyester resins and phenolics are considered criti- cal. Through the embedding of natural reinforcing Correspondence to: M. A. Khan (makhan@bangla.net). Contract grant sponsor: International Atomic Energy Agency (to M.K.A.). Journal of Applied Polymer Science, Vol. 105, 1958–1963 (2007) V V C 2007 Wiley Periodicals, Inc.