Krištoﬁč M., Vassová I., Ujhelyiová A., Ryba J.; Functionalisation of Polypropylene. Part I. Mechanical, Electric and Sorptive Properties of PP Fibres Modiﬁed with Concentrates Consisting of Copolyamides and Nanoclay. FIBRES & TEXTILES in Eastern Europe 2011, Vol. 19, No. 2 (85) pp. 18-22. 18 Functionalisation of Polypropylene. Part I. Mechanical, Electric and Sorptive Properties of PP Fibres Modiﬁed with Concentrates Consisting of Copolyamides and Nanoclay Michal Krištoﬁč, Iveta Vassová, Anna Ujhelyiová, Jozef Ryba Institute of Polymer Materials, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 812 37 Bratislava, Slovak Republic, E-mail: michal.kristoﬁc@stuba.sk Abstract Concentrates of copolyamides consisting of copolyamide (ε-caprolactam + nylon salt of adipic acid and diethylenetriamine and nylon salt of 1-(2-aminoethyl) piperazine and adipic acid) and the nanoadditive Bentonite were prepared, characterised and used for the preparation of blend polypropylene (PP) ﬁbres. PP ﬁbres modiﬁed with 4, 8 and 12 wt.% of the three types of concentrates prepared were spun without a compatibiliser by the standard melting process and drawn at three drawing ratios. Mechanical properties of the modiﬁed PP ﬁbres, i.e. tenacity and Young´s modulus, are better mainly at lower amounts of each concentrate and at higher drawing ratios. e electric properties of the modiﬁed PP ﬁbres are positively inﬂuenced by all three concentrates. e higher their amount in the modiﬁed PP ﬁbres, the better the electro- static properties. e sorptive properties of the modiﬁed PP ﬁbres, i.e. the sorption of water vapour and disperse dyestuﬀs, are much better in comparison with non modiﬁed PP ﬁbres. Key words: polypropylene, copolyamide, Bentonite, modiﬁcation, mechanical, electric, sorp- tive properties. n Introduction Due to excellent mechanical properties, high chemical stability and processabil- ity, polypropylene ﬁbres are often used in different ﬁelds. However, because of a low surface energy, lack of reactive sites and sensitivity to photo and thermal oxi- dation, their polymer properties are insuf- ﬁcient for some applications. To improve their chemical and physical properties, hydrophobic polypropylene ﬁbres can be modiﬁed by several techniques e.g. plasma treatment, chemical or physical modiﬁcation, etc. Physical modiﬁcation by the compounding of polypropylene with suitable additive(s) is a very simple way, as reported in many references. Improvement of polypropylene afﬁn- ity to polar agents such as water and dyestuffs can be effectively made with more polar (polymer) additives, such as polyamideureas and copolyamides. Hence 8 wt.% of copolyamides based on ε-caprolactam and nylon salt of 1-(2-ami- noethyl)piperazine with adipic acid [1] or 5 wt.% - 15 wt.% of copolyamides based on ε-caprolactam and nylon salt of di- ethylenetriamine with adipic acid [2] or 1 – 5 wt.% of copolyamideureas based on ε-caprolactam, urea and nylon salt of 1-(2-aminoethyl)piperazine with adipic acid [3] used as additives without a com- patibiliser improve the sorption of water vapour, dyeing from a bath and the anti- static properties of modiﬁed polypropyl- ene (PP) ﬁbres; however, these negative- ly inﬂuence their mechanical properties. Standard PP ﬁbres modiﬁed with 25 - 30 wt.% of polyamide 6 and polypro- pylene-grafted maleineanhydride as a compatibiliser or with 15 - 30 wt.% of polyethylene terephthalate and amide of stearic acid and alkylphthalate as a com- patibiliser can be prepared and effective- ly dyed from a bath with disperse dyes without a carrier [4]. If the polymer additive has a lower mo- lecular weight and no compatibiliser is added, lower mechanical properties of the modiﬁed ﬁbres are usually obtained [5]. On the other hand, the addition of a polymer additive with a high molar weight (e.g. nanoadditive) can improve the mechanical properties of blends and ﬁbres prepared therefrom. Moreover this nanoadditive can form an intercalated or exfoliated hybrid with the polymer additive. It is important to note that the molecular weight of the nanoadditive platelets is considerably greater (cca 1.3 × 10 8 ) than that of typical commercial polymers. In addition, platelets are not totally rigid but have a degree of ﬂex- ibility [6]. The substantial enhancement of the nanocomposite properties is attrib- uted to the ultra ﬁne phase dimensions of the ﬁller in the polymer matrix, which can be observed in the swelling of nano- clay with the monomer and synthesis of the polymer additive in the presence of