At the last ANTEC meeting (May 8-10th 2017 in Anaheim, CA) a rotation molding session was organized on the Monday morning to celebrate the 75th anniversary of the SPE. For this occasion, a series of presentation coming from different parts of the world (Canada, China, Germany and Mexico) reported on new developments related to materials, processing and characterization of rotomolded products. The session was well attended and generated lively discussions between the presenters and the attendees. A list of the presentation is given here with their respective abstract (the speaker is underlined).

 

 

1) INFLUENCE OF PARTICLE SIZE IN MULTI-LAYER ROTATIONAL MOLDING WITH A MULTIPHASE INTERLAYER TO GENERATE MECHANICAL ADHESION

 

Martin Löhner and Dietmar Drummer, Institute of Polymer Technology (LKT),

Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

 

Abstract

Rotational molding shows the potential to build up multi-layer parts by sequential adding of different materials into a rotating cavity. The limited compatibility of several materials to each other reduces the potential material combinations significantly. Former investigations showed the general applicability of a multi-phase interlayer to bond incompatible materials during the rotational molding process. Within this interlayer interlocking occurs between the two materials. This work investigates the influence of particle size on the material distribution and peel strength for the material combination Polyethylene and Polyamide 12. It is shown, that the material distribution is depending on the particle size added to generate the interlayer whereas the peel strength is mostly unaffected if the interlayer thickness exceeds the particle size. For thinner interlayers smaller particles show higher peel strengths and a varying interphase region.

 

 

 

2) PREPARATION OF PA6/LLDPE BLENDS BY ROTATIONAL MOLDING

Rubén González-Núñez, Rosa Gabriela López-GonzalezNúñez, Pedro Ortega Gudiño, Milton O. Vázquez-Lepe, Universidad de Guadalajara. Mexico and Denis Rodrigue, Université Laval. Canada

 

Abstract

Blends of linear low density polyethylene (LLDPE) and polyamide 6 (PA6) were produced by rotational molding. Blends of 10, 20 and 30% vol. of PA6 in LLDPE were previously prepared using two methods: dry blending using a high shear mixer, and melt-compounding using a twin-screw extruder. The objective of the work is to study the morphological and mechanical properties of rotomolded parts of polymer blends. The results indicated that the rotomolded parts of the blends obtained by previous extrusion generated smaller and better dispersed PA6 particles in the LLDPE matrix. The mechanical properties are also found to be influenced by the blend preparation method.

 

 

3) ROTATIONAL MOLDING OF POLYLACTIC ACID AND AGAVE FIBER BIOCOMPOSITES

E.O. Cisneros-López, A.A. Pérez-Fonseca, D.E. Ramírez-Arreola, R. González-Núñez, Y. González-García, J.R. Robledo-Ortíz, Universidad de Guadalajara, México and D. Rodrigue, Université Laval, Canada

 

Abstract

In this work, biocomposites of agave fibers (Agave tequilana Weber var. Azul) and polylactic acid (PLA) were produced by rotational molding. In particular, a simple dry-blending technique was used to disperse the agave fibers in the biodegradable polymer matrix. The effect of fiber content was studied (0, 10, 20, 30, and 40 wt.%) and the samples were characterized in terms of morphology, density and porosity to relate with mechanical properties (tensile, flexion, impact and hardness). The results showed that rotomolded biocomposites were successfully produced, but had high porosity leading to lower properties for fiber contents above 10%. It was possible to observe that low fiber contents produced the best morphology, indicating that there is an optimum fiber content to get well-distributed fibers in the matrix.

 

 

 

4) Relationships between Low Temperature Impact Performance and Structures of Rotationally Molded Crosslinked High Density Polyethylene

Yueqing Renab, Xia Dongb, Xuelian Chena, Xiaojie Suna, Shuguang Wanga, Yafei Lia, Dujin Wangb, Wenbin Lianga

a Department of polymer materials, Advanced materials center, National institute of Clean-and-Low-Carbon Energy, Beijing 102211, China

b Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences,

Beijing 100190, China

 

Abstract

The low temperature impact performance of rotationally molded specimen is of great importance for the final products. Crosslinked high density polyethylene (XL-HDPE) is a preferred material for large chemical and fuel tank due to its superior environmental stress crack resistance and high impact strength. In the present research the drop weight impact strength (defined as ARM impact strength) of rotationally molded XL-HDPE was carried out at -40 °C and the relationships between impact strength and microstructures were investigated. The results confirmed that the microstructures of XLHDPE molecules in the innermost surface layer dominated the low temperature impact performance of rotationally molded XL-HDPE articles.

 

 

 

5) ROTATIONAL MOLDING OF LINEAR LOW DENSITY POLYETHYLENE WITH DIFFERENT CONCENTRATIONS OF GROUND TIRE RUBBER

Y. Dou, D. Rodrigue, Université Laval, Canada

 

Abstract

In this work, ground tire rubber (GTR) was dry-blended with linear low density polyethylene (LLDPE) to produce thermoplastic elastomer parts by rotational molding. In particular, different GTR concentrations (0, 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50% wt.) were incorporated to determine the effect of the rubber phase on the processability and overall properties of the parts. Each composition was characterized in terms of morphology and mechanical properties (tensile, flexural and impact). The results show that the addition of the rubber phase decreased the tensile and flexural moduli and strengths, but the tensile elongation at break was always above 100%. This good elasticity produced impact strengths higher than the neat matrix with an optimum GTR content around 20% wt.

 

 

The next ANTEC meeting will take place from May 7th to the 9th at the Orange County Convention Center in Orlando (FL). The meeting will be jointly organized with NPE (National Plastics Exhibition) which is the largest plastics show in North America. I personally invite you all to come and join us for this event.