Preparation and characterizations of HDPE–EVA alloy/OMT nanocomposites/paraffin compounds as a shape stabilized phase change thermal energy storage material

Abstract A kind of shape stabilized phase change nanocomposites materials (PCNM) based on high density polyethylene (HDPE)/ethylene-vinyl acetate (EVA) alloy, organophilic montmorillonite (OMT), paraffin and intumescent flame retardant (IFR) are prepared using twin-screw extruder technique. The structures of the HDPE–EVA alloy/OMT nanocomposites are evidenced by the X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that an ordered intercalated nanomorphology of the HDPE–EVA alloy/OMT nanocomposites is formed. Then the structures of the shape stabilized PCNM are characterized by scanning electron microscopy (SEM). The HDPE–EVA alloy/OMT nanocomposites act as the supporting material and form the three-dimensional network structure. The paraffin acts as a phase change material and disperses in the three-dimensional network structure. Its latent heat is given by differential scanning calorimeter (DSC) method. The SEM and DSC results show that the additives of IFR have little effect on the network structure and the latent heat of shape stabilized PCNM, respectively. The thermal stability properties are characterized by thermogravimetric analysis (TGA). The TGA analysis results indicate that the flame retardant shape stabilized PCNM produce a larger amount of char residue at 800 °C than that of shape stabilized PCNM, although the onset of weight loss of the flame retardant shape stabilized PCNM occur at a lower temperature. The formed multicellular char residue contributes to the improvement of thermal stability performance. The probable combustion mechanisms are also discussed in this paper.

[1]  C. A. Wilkie,et al.  Thermal and Fire Studies on Polystyrene-Clay Nanocomposites , 2000 .

[2]  Takashi Kashiwagi,et al.  PA-6 clay nanocomposite hybrid as char forming agent in intumescent formulations , 2000 .

[3]  Michel Le Bras,et al.  Press Release: Fire Retardancy of Polymers: The use of Intumescence , 1998, Engineering Plastics.

[4]  S. Bourbigot,et al.  The Use of Clay in an EVA-Based Intumescent Formulation. Comparison with the Intumescent Formulation Using Polyamide-6 Clay Nanocomposite As Carbonisation Agent , 2001 .

[5]  Yuan Hu,et al.  Influence of gamma irradiation on high density polyethylene/ethylene‐vinyl acetate/clay nanocomposites , 2004 .

[6]  X. Py,et al.  Paraffin/porous-graphite-matrix composite as a high and constant power thermal storage material , 2001 .

[7]  Ye Hong,et al.  Preparation of polyethylene–paraffin compound as a form-stable solid-liquid phase change material , 2000 .

[8]  Min Xiao,et al.  Preparation and performance of shape stabilized phase change thermal storage materials with high thermal conductivity , 2002 .

[9]  Zhengguo Zhang,et al.  Study on paraffin/expanded graphite composite phase change thermal energy storage material , 2006 .

[10]  S. Bourbigot,et al.  Carbonization mechanisms resulting from intumescence association with the ammonium polyphosphate-pentaerythritol fire retardant system , 1993 .

[11]  T. Kashiwagi,et al.  Cone Calorimeter Combustion and Gasification Studies of Polymer Layered Silicate Nanocomposites. , 2002 .

[12]  A. Okada,et al.  Preparation and Mechanical Properties of Polypropylene−Clay Hybrids , 1997 .

[13]  P. Dubois,et al.  Polymer-layered silicate nanocomposites: preparation, properties and uses of a new class of materials , 2000 .

[14]  S. Bourbigot,et al.  Using polyamide-6 as charring agent in intumescent polypropylene formulationsI. Effect of the compatibilising agent on the fire retardancy performance , 2002 .

[15]  W. Fan,et al.  PA‐6 and EVA alloy/clay nanocomposites as char forming agents in poly(propylene) intumescent formulations , 2005 .

[16]  Shih-hsuan Chiu,et al.  Dynamic flame retardancy of polypropylene filled with ammonium polyphosphate, pentaerythritol and melamine additives , 1998 .

[17]  Ahmet Sarı,et al.  Form-stable paraffin/high density polyethylene composites as solid–liquid phase change material for thermal energy storage: preparation and thermal properties , 2004 .

[18]  Zhengguo Zhang,et al.  A novel montmorillonite-based composite phase change material and its applications in thermal storage building materials , 2006 .

[19]  René Delobel,et al.  Thermal Behaviours of Ammonium Polyphosphate-Pentaerythritol and Ammonium Pyrophosphate-Pentaerythritol Intumescent Additives in Polypropylene Formulations , 1990 .

[20]  H. Inaba,et al.  Evaluation of thermophysical characteristics on shape-stabilized paraffin as a solid-liquid phase change material , 1997 .

[21]  S. Bourbigot,et al.  Carbonization mechanisms resulting from intumescence-part II. Association with an ethylene terpolymer and the ammonium polyphosphate-pentaerythritol fire retardant system , 1995 .

[22]  Min Xiao,et al.  Thermal performance of a high conductive shape-stabilized thermal storage material , 2001 .

[23]  Jiang Yi,et al.  Modeling and experimental study on an innovative passive cooling system—NVP system , 2003 .

[24]  Jeffrey W. Gilman,et al.  Flammability and thermal stability studies of polymer layered-silicate (clay) nanocomposites , 1999 .

[25]  R. E. Smallman,et al.  An assessment of high voltage electron microscopy (HVEM). An invited review , 1977 .

[26]  Yuan Hu,et al.  Flammability and thermal properties of high density polyethylene/paraffin hybrid as a form‐stable phase change material , 2006 .

[27]  Marco Zanetti,et al.  Thermal behaviour of poly(propylene) layered silicate nanocomposites , 2001 .