Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Institution Author: search.filters.institutionAuthor.Demir, HasanSubject: search.filters.subject.Polypropylene

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  • Article
    Citation - WoS: 71
    Citation - Scopus: 87
    Influence of Surface Modification of Fillers and Polymer on Flammability and Tensile Behaviour of Polypropylene-Composites
    (Elsevier Ltd., 2006) Demir, Hasan; Balköse, Devrim; Ülkü, Semra
    An intumescent system consisting of ammonium polyphosphate (APP) as an acid source and blowing agent, pentaerythritol (PER) as a carbonific agent and natural zeolite (clinoptilolite, Gördes II) as a synergistic agent was used in this study to enhance flame retardancy of polypropylene (FR-PP). Zeolite was incorporated into flame retardant formulation at four different concentrations (1, 2, 5, and 10 wt%) to investigate synergism with the flame retardant materials. Filler content was fixed at 30 wt% of total amounts of flame retardant PP composites. Zeolite and APP were treated with two different coupling agents namely, 3-(trimethoxysilyl)-1-propanethiol and (3-aminopropyl)-triethoxysilane for investigation of the influence of surface treatments on mechanical properties and flame retardant performance of composites. Maleic anhydride grafted polypropylene (MAPP) was used for making polypropylene hydrophilic. Flammability of FR-PP composites was measured by the determination of limiting oxygen index (LOI). The LOI values reached to a maximum value of 41% for mercapto silane treated APP:PER (2:1) PP composite containing 5 wt% zeolite. The tensile strength of composites was increased by the addition of MAPP and elongation at break of composites was increased with silane treatments.
  • Article
    Citation - WoS: 35
    Citation - Scopus: 39
    Optimisation of the Effect of Colemanite as a New Synergistic Agent in an Intumescent System
    (Elsevier Ltd., 2006) Atikler, Ulaş; Demir, Hasan; Tokatlı, Figen; Tıhmınlıoğlu, Funda; Balköse, Devrim; Ülkü, Semra
    An intumescent system including ammonium polyphosphate (APP) as an acid source and blowing agent, pentaerythritol (PER) as a carbonific agent and colemanite as a synergistic agent is used to enhance flame retardancy of polypropylene (FR-PP). In order to investigate the synergism between colemanite and the flame retardant materials (APP and PER), D-optimal mixture design was employed. The limiting oxygen index (LOI) and amount of residue (AoR) were accepted as response 1 and response 2, respectively. Applying D-optimal strategy, 18 experiments were performed. Filler content was fixed at 30 wt% of total amounts of flame retardant PP composites. Constraints were determined according to the ratio of APP/PER ranging between 1 and 3. Statistical analysis of the cubic model revealed that lack of fit (LoF) was not significant for the cubic and linear model for both responses. The model suggested an optimum composite formulation with concentration levels 65% of APP, 28% of PER and 7% of colemanite that gives an LOI of 40.3. The experimental LOI and AoR of optimum formulation were achieved as 39.3 and 21.4 with 2.5% and 2.2% errors, respectively.