Influences of halloysite nanotubes on crystallisation behaviour of polylactide

Date

2015-03-01

Author

Kaygusuz, I.
Kaynak, Cevdet

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

206
views

0
downloads

The aim of this study was to investigate influences of halloysite nanotubes (HNTs) on the (i) isothermal and (ii) non-isothermal crystallisation kinetics of polylactide (PLA) by differential scanning calorimetry (DSC) analyses, and (iii) crystallinity of injection moulded and then annealed specimens by DSC and X-ray diffraction (XRD) analyses. Nanocomposites were compounded using melt mixing technique via twin screw extrusion. Owing to basically very effective heterogeneous nucleation effect, addition of HNTs resulted in significant increases in the crystallinity of PLA under all three cases. Crystallisation time parameters and Avrami rate constants indicated that crystallisation rate increased under isothermal crystallisation, while it decreased under non-isothermal crystallisation due to the delayed conformational mobility of PLA chains by the physical barrier actions of HNTs. Avrami exponent also revealed that two-dimensional growth mechanism of crystallites transformed into three-dimensional growth during non-isothermal crystallisation, while there was no change during isothermal crystallisation. Crystallinity determinations of the injection moulded and then annealed specimens indicated that, the highest crystallinity degree of PLA, i. e. 47%, could be reached by the addition of only 1 wt-% HNT.

Subject Keywords

Halloysite nanotubes, Annealing, Non-isothermal crystallisation, Isothermal crystallisation, Polylactide

URI

https://hdl.handle.net/11511/36870

Journal

PLASTICS RUBBER AND COMPOSITES

DOI

https://doi.org/10.1179/1743289814y.0000000116

Collections

Department of Metallurgical and Materials Engineering, Article

Suggestions

OpenMETU
Core

Mechanical and thermal properties of polylactide/talc microcomposites: before and after accelerated weathering Kaynak, Cevdet (2016-06-01) The purpose of the first part of this study was to investigate effects of micron-sized talc content on the properties of polylactide (PLA). PLA/talc microcomposites were compounded by melt-mixing method via twin-screw extruder, while specimens for testing and analyses were shaped by injection molding. It was observed that, because of the effective stiffening, strengthening, toughening mechanisms of talc, and also their nucleation agent effects for higher crystallinity, many mechanical and thermal properties...
Risky Play in Early Childhood Education: A Risk Worth Taking Yalçın, Fatma; Erden, Feyza (2018-12-01) This paper aimed to present a literature review, examine relevant studies and present their common aims and findings. Based on this review, the study also intended to discuss and evaluate the current status of risky play in Turkish early childhood education. The literature was chosen through online sources, including several books, reports and many articles in the journals. A comprehensive research was conducted through data bases including ERIC, SCOPUS, ULAKBIM and Complementary Index using the key words s...
Social identity and constructions of European Union among Turkish University youth Cem, Nevra; Hortaçsu, Nuran; Department of Psychology (2003) The aim of this study was twofold: to investigate (i) the relationship between values, social identities, constructions of European Union (EU) and (ii) reactions to December 12th Copenhagen decision concerning Turkey. In order to fullfil the aim, two methodologically different analyses were carried out: A qualitative analysis of newspapers representing different ideologies, and a quantitative analysis of Turkish university students̕ responses to questionaries. The qualitative analysis revealed different con...
USE OF A SOCIAL COGNITIVE THEORY-BASED PHYSICAL-ACTIVITY INTERVENTION ON HEALTH-PROMOTING BEHAVIORS OF UNIVERSITY STUDENTS İnce, Mustafa Levent (SAGE Publications, 2008-12-01) The purpose of this study was to examine the effects of a 12-wk. physical activity intervention, based on conceptual discussions and practices of a social cognitive theory on health-promoting behaviors of 62 university students. The intervention Mainly focused on development of self-regulatory skills, social support, and self-assessment of health-related fitness. The Adolescent Health Promotion Scale and International Physical Activity Questionnaire were given Analysis of self-reports indicated improved nut...
Influences of aminosilanization of halloysite nanotubes on the mechanical properties of polyamide-6 nanocomposites Erdogan, Ali Riza; Kaygusuz, Ilker; Kaynak, Cevdet (Wiley, 2014-07-01) The main purpose of this study was to explore effects of silanization of halloysite nanotubes (HNT) on the mechanical properties of polyamide 6 by using aminopropyltriethoxysilane. Effects of two silanization parameters; initial silane concentration and pH of reaction solution were also investigated. Nanocomposites were compounded via melt mixing method in a twin-screw extruder, while specimens were shaped by injection molding. Formation of aminosilane molecules on the edges and defected surfaces of HNTs we...

Citation Formats

I. Kaygusuz and C. Kaynak, “Influences of halloysite nanotubes on crystallisation behaviour of polylactide,” PLASTICS RUBBER AND COMPOSITES, pp. 41–49, 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36870.