Preparation of crosslinkable high density polyethylene and polypropylene polyblends

Download
2015
Koltuksuz, Barış
High density polyethylene (HDPE) and polypropylene (PP) are two commonly used thermoplastic polymers existing in the commodity plastic market due to their developed and easy post-reactor processability characteristics. Although these two polymers can be subjected to reprocessing, they eventually experience critical losses in their main physical and mechanical properties at elevated temperatures. With the aim of preventing these losses in their mechanical and thermal properties in their individual and blended states, this thesis presents a unique way of processing the blends of the sought polymer components incorporated with dicumyl peroxide (DCP). The two polymers were extruded with weight percentages of 30%, 50%, and 70% for each polymer. Followed by the swelling of the pellets in hexane-DCP solution, they were processed into films in a hot-press. The data obtained as a result of tensile testing performed on the specimens taken from the prepared films showed that the Young’s moduli of individual PP set incorporated with 1.0% (w/w) DCP, 30HDPE70PP set incorporated with 0.5% (w/w) DCP, and 50HDPE50PP set incorporated with 0.5% (w/w) DCP were increased by 28.5%, 28.4%, and 2.45% compared to their pristine values, respectively. The tensile strength of 30HDPE70PP set at 2.0% (w/w) DCP level experienced a small increase. The percentage elongation of 70HDPE30PP set was increased from its pristine value of 8% to 30%, 44%, and 98% with addition of 0.5% (w/w), 1.0% (w/w) and 2.0% (w/w) DCP, respectively. Upon processing the blends with DCP and applying differential scanning calorimetry (DSC) analysis to their specimens, their percent crystallinities were calculated from the analysis outputs. The mechanical results are mutually explained via the simultaneous interpretation of the calorimetric analysis data.

Suggestions

Synthesis of Emulsion-Templated Acrylic-Based Porous Polymers: From Brittle to Elastomeric
Tunc, Yeliz; Hasırcı, Nesrin; ULUBAYRAM, KEZBAN (2012-01-01)
High internal phase emulsion polymers (PolyHIPEs) are novel materials that have high porosity and interconnected open-cell structure and are used in various applications such as supports for catalytic systems, media for separation of similar molecules, and scaffolds for tissue engineering. In this study, 90% porous acrylic based polyHIPE structures with various cellular structure and mechanical characteristics were developed by using stearyl acrylate (SA), isodecyl acrylate (IDA), isobornyl methacrylate (IB...
Characterization of Ti6Al7Nb alloy foams surface treated in aqueous NaOH and CaCl2 solutions
Butev, Ezgi; ESEN, ZİYA; Bor, Sakir (2016-07-01)
Ti6Al7Nb alloy foams having 53-73% porosity were manufactured via evaporation of magnesium space holders. A bioactive 1 mu m thick sodium hydrogel titanate layer, NaxH2-xTiyO2y+1., formed after 5 M NaOH treatment, was converted to crystalline sodium titanate, Na2TiyO2y+1, as a result of post-heat treatment. On the other hand, subsequent CaCl2 treatment of NaOH treated specimens induced calcium titanate formation. However, heat treatment of NaOH-CaCl2 treated specimens led to the loss of calcium and disappea...
PREPARATION OF BLOCK-COPOLYMERS WITH MACROAZONITRILES AS THE INITIATOR
YURUK, H; ULUPINAR, S (Wiley, 1993-12-01)
Block copolymers containing poly(ethylene oxide) or poly(propylene oxide) prepolymer segments and methyl methacrylate were prepared. A stepwise procedure was first employed to prepare macro-azocarbamates by capping hydroxy-terminated poly(ethylene oxide) or poly(propylene oxide) with 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate and subsequently reacting this intermediate with 4,4'-azobis(4-cyano-n-pentanol)**. The resulting polymeric azocarbamates were used as free-radical initiators for the poly...
The formation of smooth, defect-free, stoichiometric silicon carbide films from a polymeric precursor
Pitcher, Michael; Bianconi, Patricia (2006-04-20)
Silicon carbide (SiC) materials, which are used in a variety of applications, are often produced using powder processing, sintering or bulk crystal growing techniques. The formation of silicon carbide films or shaped products, via these methods, is often extremely difficult and/or requires high temperatures. Here we report the synthesis and characterization of a polymeric precursor, Polymethylsilyne (PMSy), and it subsequent conversion to beta-SiC. The polymer is simple to synthesize and is easily manipulat...
Determination of cracking related properties of engineering cementitious composites
Keskin, Süleyman Bahadır; Şahmaran, Mustafa; Yaman, İsmail Özgür (null; 2017-09-12)
Engineered Cementitious Composites (ECC) are relatively new types of fiber reinforced cementitious materials with enhanced mechanical properties such as tensile strain hardening accompanying high tensile strain capacity. This is mainly attributed to close and multiple cracks with widths remaining under 60 µm which contributes to durability of ECC material. These properties are only achievable as a result of a micro-mechanical design that requires special ingredients that make ECC costly to be used alone, ho...
Citation Formats
B. Koltuksuz, “Preparation of crosslinkable high density polyethylene and polypropylene polyblends,” M.S. - Master of Science, Middle East Technical University, 2015.