TEXTILE MANAGEMENT
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Study on Metallocene Catalyst and Ziegler-Natta Catalyst Sandeep Vinod Vishwakarma Guided by: Prof. S.G.Kulkarni D.K.T.E Society’s Textile & Engineering Institute, Ichalkaranji-416116, Kolhapur Abstract Fifty years ago, Karl Ziegler and Natta were awarded by the Nobel Prize for his discovery of catalytic polymerization of ethylene and propylene using the titanium compounds with aluminum-alkyls as co-catalysts. Polyolefins has grown to become one among the most important produced polymers. New metallocene/methylaluminoxane (MAO) catalysts opens the likelihood for synthesize polymers with highly defined microstructure, tacticity and steroregularity, also like longchain branched or blocky copolymers with excellent properties. This paper reviews melt spinning of the fibers of metallocene catalyzed isotactic polypropylene (PP) and standard equivalent of Ziegler-Natta isotactic Polypropylene (PP); the properties of PP and a few thermal and mechanical properties of fiber. Ziegler-Natta catalysts is prepare by reaction which employed Mg (OEt) 2 as a precurosor. The newly developed Metallocene catalyst PP possesses higher isotacticity and crystallinity than the commercial ones, which assures the mechanical properties of the final products. KEYWORDS: Catalysts, Metallocene, Polypropylene, Polyolefins, ZieglerNatta. Introduction Nonwoven fabric became a particularly important segment of the textile industry. Compared to the global market average of 24%, Indian market has a 12% share of technical textiles which are being manufacture by non-woven technology. The Non-woven market is expected to grow from USD 40.5 bil-
lion in 2020 to USD 53.5 Billion by 2025. For the manufacturing of nonwoven fabric, different web formation methods are used; Dry Laid nonwoven, Spun laid nonwoven and wet-laid non-woven. These are supported web bonding; Mechanical bonding, Thermal Bonding and Chemical Bonding. The bonding types, the fiber type and therefore the manufacturing parameters determine the characteristic feature of non-woven. In contrast to standard engineering materials, these fabrics have better specific mechanical properties, strength to weight and stiffness to weight ratios [1]. Melt Blown and Spun laid nonwoven are most generally used method for the production of nonwoven fabric. Melt blown nonwovens are made in one continuous process. Fibers are spun, then directly dispersed into a web by deflectors or are often directed with air streams. This results in faster belt speed and cheaper costs. Spun laid also called spun bond, nonwoven fabric are produced by extruding melted polymer fibers through a spin net or die consisting of upto 40 holes per inch to create long thin fibers which are stretched and cooled by passing hot air over the fibers as they fall from die. The approaching web is collected into rolls and subsequently converted to finished products. Spun blown plays a role of imparting strength to the nonwoven fabric and Melt blown is employed for Barrier Properties of nonwoven fabric.
fabric. It is made from top layer of spun bond polypropylene, a middle layer of melt blown polypropylene and a bottom layer of spun bond polypropylene. Polypropylene is a downstream petrochemical product derived from the olefin monomer, propylene. The polymer is produced through a process of monomer connection called addition polymerization normally by using the Ziegler-Natta catalyst System. ZieglerNatta is heterogeneous catalyst, the primary efficient and stereospecific catalyt. Catlystic polymerization method was developed by Karl Ziegler and Natta in 1950. Isotactic polypropylene resins had been produced from ZieglerNatta catalysts for over 45 years now. the upper relative molecular mass and broad relative molecular mass distribution were characteristic for resins as produced within the polymerization reactor. The features of metallocene isotactic PP are uniformity in polymer with narrow relative molecular mass which is convenient for fiber spinning [2, 5].
Differing types of polymers are utilized in the assembly of nonwoven fabric like Polyester, PET, Polypropylenes; they are either in the form of small chips or in the form of powder. Spun bond Melt blown Spun bond, commonly called SMS could be a tri laminate non-woven
Homogeneous catalysts
1.1 Heterogeneous catalysts These are industry-dominating catalysts that are supported titanium compounds (and sometimes vanadium-based) and used for polymerization reactions; usually together with organo-aluminum compounds, like triethylaluminium (TEA=Al (C2H5)3) as co-catalysts [3]. These are the second broad class of catalysts and are supported complexes of Ti, Zr, or Hf. They are generally used in combination with a variety of organoaluminum co-catalysts called metallo-
MARCH 2021
