Synthesis and characterization of polyethylene-octene elastomer/clay/biodegradable starch nanocomposites

Synthesis and Characterization of Polyethylene-Octene
Elastomer/Clay/Biodegradable Starch Nanocomposites
Hsin-Tzu Liao, Chin-San Wu
Department of Biochemical Engineering and Graduate Institute of Environmental Polymer Materials, Kao Yuan Institute of Technology, Kaohsiung County, Taiwan 82101, Republic of China Received 20 April 2004; accepted 10 December 2004DOI 10.1002/app.21763Published online in Wiley InterScience (www.interscience.wiley.com).
ABSTRACT:
The aim of this work is the production of g-AA chains to intercalate into clay layers. Based on consid- new nanocomposites from metallocene polyethylene-octene eration of thermal and mechanical properties, it is also found elastomer (POE), montmorillonite and biodegradable starch that 12 wt % of clay content is optimal for preparation of by means of a melt blending method. Characterizations of POE-g-AA/clay nanocomposites. The new partly biodegrad- clay, modified clay, POE, POE-g-AA, and the hybrids pro- able POE-g-AA/clay/starch hybrid could obviously im- duced from polymer, clay, and/or starch were performed by prove the elongation and the tensile strength at break of the X-ray diffraction (XRD) spectroscopy, Fourier transform in- POE-g-AA/starch hybrid since the former can give the frared (FTIR) spectrophotometer, differential scanning calo- smaller starch phase size and nanoscale dispersion of silicate rimetry (DSC), thermogravimetry analyzer (TGA), scanning layers in the polymer matrix. The nanocomposites produced electron microscope (SEM), and Instron mechanical tester.
from our laboratory can provide a stable tensile strength at As to the results, organophilic clay can be well dispersed break when the starch content is up to 40 wt %. 2005 Wiley into acrylic acid grafted polyethylene-octene elastomer Periodicals, Inc. J Appl Polym Sci 97: 397– 404, 2005 (POE-g-AA) in nanoscale sizes since cetyl pyridium chlorideis partially compatible with POE-g-AA and allows POE- Key words: polyethylene; octane; clay; surfactant
INTRODUCTION
clay hybrids has been studied by Yano and col-leagues.18 In their study, hectrite, saponite, montmo- Inorganic clay minerals, such as montmorillonite and rillonite, and synthetic mica were used as clay miner- hectrite, have been widely used as reinforcement ma-terials for polymers due to their nanoscale size and als, and the results showed that the longer the length intercalation properties.1–3 In recent years, polymer/ of clay mineral was, the more effectively properties of silicate hybrid nanocomposites have been of consider- able interest as an effective method to develop new Polyethylene is one of the most widely used poly- composite materials. There are two commercially at- olefin polymers, but its use is restricted in certain tractive approaches, in situ polymerization and melt applications by its low melting point, biodegradabil- exfoliation, for preparing polymer/clay nanocompos- ity, stability in hydrocarbons, and a tendency to crack ites. The first method has been used for preparation of when stressed. Research on graft reaction, crosslink- nylon 6-clay hybrid, and the results showed that ing reaction, and blending with inorganic fillers for strength, modulus, and heat distortion temperature of polyethylene, to mitigate its disadvantages, have been virgin nylon 6 could be increased markedly.4–7 The extensively investigated for many years. Recently, the melt intercalation method was first demonstrated by metallocene based polyethylene-octene elastomer Vaia and coworkers,2 and then it became a main- (POE), which is developed using a metallocene cata- stream for the preparation of polymer/clay nanocom- lyst by Dow and Exxon, has received much attention posites without in situ interactive polymerization, es- due to its unique uniform distribution of comonomer pecially for the case of polyolefin-based nanocompos- content and narrow molecular weight distribution.19,20 It seems that study on synthesis and characterization preparation of polypropylene/clay and polyethylene/ of POE/clay nanocomposites using the melt exfolia- clay nanocomposites.10–17 The effect of size and type tion method has not been found in our literature sur- of the clay minerals to the properties of polyimide/ vey, though researches of PE/clay and PP/clay nano-composites have been proposed in the past.
Since POE does not include any polar groups in its Correspondence to: H.-T. Liao ([email protected]).
backbone, it is thought that homogeneous dispersionof the hydrophilic clay minerals in the hydrophobic Journal of Applied Polymer Science, Vol. 97, 397–404 (2005) 2005 Wiley Periodicals, Inc.
POE matrix is not realized. In general, the clay is

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