Improved Electromagnetic Shielding Performance of Lightweight Compression Molded Polypyrrole/Ferrite Composite Sheets SWATI VARSHNEY 1 and S.K. DHAWAN 2,3 1.—Delhi Institute of Tool Engineering, Okhla, New Delhi 110020, India. 2.—Polymeric and Soft Materials Section, National Physical Laboratory (CSIR), New Delhi 110012, India. 3.—e-mail: skdhawan@mail.nplindia.org An attempt has been made to design lightweight polypyrrole/carbon fibers and polypyrrole/carbon fibers/ferrofluid (Fe 3 O 4 particles) composite sheets using novolac resin via compression molding for electromagnetic shielding applica- tions. The optimized formulation has been achieved to get an excellent com- bination of thermal, mechanical, and electrical properties of the composite sheet. Structural and morphological studies were carried out by x-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Polypyrrole/carbon fibers composite sheets shows maximum flexural strength and a flexural modulus of 62.4 ± 1 MPa and 0.60 ± 0.02 GPa, respectively, with total shielding effectiveness of 22.8 dB in the Ku-band (12.4–18 GHz) but when ferrofluid is added to the polypyrrole/carbon fibers composite system, flexural strength increases to 92.3 ± 1 MPa and the same trend has been observed for flexural modulus with a value of 0.65 ± 0.04 GPa. This multiphase lightweight polypyrrole com- posite sheet having 34 vol.% of carbon fibers and 4 vol.% of Fe 3 O 4 nanopar- ticles offers total shielding effectiveness of 31.9 dB ( >99.99% attenuation) in the Ku-band (12.4–18 GHz) frequency range with a thickness of 1.25 mm. This is accredited to high dielectric losses and magnetic losses in conducting composite sheets. The observed results suggest that lightweight compression molded polypyrrole composite sheets could be a potential commercial alter- native for electromagnetic shielding applications. Key words: Polypyrrole, composite, shielding, compression molding INTRODUCTION Our incipient generation is better called the ‘multimedia generation’ as we all are habitual and crazy to keep one or more than one electronic contrivances. All of us spend most hours of the day with mobile phones, computers, television, multi- media gadgets, video games and other technology contrivances. Concurrently, the immense use of these electronic contrivances engenders an incipient kind of pollution known as electromagnetic (EM) pollution. This electromagnetic pollution not only adversely affects the operation of electronic devices, but also deteriorates human health and is respon- sible for many diseases like a headache, stress, memory loss, infertility, cancer, etc. 1 Considering the indispensable role of electronics in our lives, the scientists are canvassing ways to neutralize harm- ful electromagnetic radiations. Their aim is to cut the amount of radiation to almost zero. With due reason, electromagnetic wave absorbing materials have gained much attention as a solution against EM pollution. High conductivity, magnetic perme- ability, thickness and dielectric constant are some consequent material parameters that decide the electromagnetic shielding effectiveness of a mate- rial. 2,3 Besides these properties, lightweight and (Received June 28, 2016; accepted December 15, 2016; published online January 5, 2017) Journal of ELECTRONIC MATERIALS, Vol. 46, No. 3, 2017 DOI: 10.1007/s11664-016-5233-7 Ó 2016 The Minerals, Metals & Materials Society 1811