Sage Journals: Discover world-class research

Abstract

Uniform foams (UF) and density graded foams (DGF) were produced by using similar or different temperatures on both sides of a compression molding system. The samples were produced using linear low density polyethylene as the matrix and activated azodicarbonamide as the chemical blowing agent. Morphological properties of the produced samples were analyzed via scanning electron microscopy to relate them to their mechanical properties. In particular, flexural and impact properties are reported for samples produced under a range of temperatures (140–200°C) and blowing agent concentration (0.7–1.0 wt%). The experimental results showed that a significant difference can be obtained in flexural modulus (up to 17%) and impact strength (up to 48%) depending on the side the stress is applied on. In all cases, the DGF showed better mechanical responses than UF of similar relative density for the range of conditions tested.

Keywords

Polyethylene density graded foam flexural modulus impact strength

Get full access to this article

View all access options for this article.

References

Niino

Maeda

. Recent development status of functionally gradient materials. ISIJ Int 1990; 13: 699–703.

Poveda

Gupta

. Weight-saving potential of open- and closed-cell functionally graded foams under compressive loading. Int J Crashworth 2012; 17: 497–507.

Kelly

Arora

Worley

. Sandwich panel cores for blast applications: materials and graded density. Exp Mech 2016; 56: 523–544.

Tovar-Cisneros

Gonzalez-Nuñez

Rodrigue

. Effect of mold temperature on morphology and mechanical properties of injection molded HDPE structural foams. J Cell Plast 2008; 44: 223–237.

Yao

Rodrigue

. Density graded polyethylene foams produced by compression moulding using a chemical blowing agent. Cell Polym 2012; 31: 189–205.

Tissandier

González-Núñez

Rodrigue

. Asymmetric microcellular composites: mechanical properties and modulus prediction. J Cell Plast 2016; 52: 365–398.

Yao

Barzegari

Rodrigue

. Density graded linear medium density polyethylene foams produced under a temperature gradient with expancel microbeads. Cell Polym 2011; 30: 157–185.

Al Jahwari

Huang

Naguib

. Relation of impact strength to the microstructure of functionally graded porous structures of acrylonitrile butadiene styrene (ABS) foamed by thermally activated microspheres. Polymer 2016; 98: 270–281.

Zhu

Wang

. Controllable fabrication of graded and gradient porous polypropylene. J Porous Mater 2015; 22: 119–125.

10.

Chittineni

Woldesenbet

. Characterization of integrated functionally gradient syntactic foams. J Eng Mater Tech 2010; 132: 011005.

11.

Elsing

Quell

Stubenrauch

. Toward functionally graded polymer foams using microfluidics. Adv Eng Mater 2017; 19: 1700195.

12.

Rodrigue

. Using density profiles to predict the flexural modulus of structural polymer foams. J Cell Plast 2008; 44: 381–389.

13.

Barzegari

Yao

Rodrigue

. Compression molding of polyethylene foams under a temperature gradient: morphology and flexural modulus. Cell Polym 2009; 28: 237–248.

14.

Barzegari

Twite-Kabamba

Rodrigue

. Flexural modulus prediction of symmetric structural polymer foams with complex density profiles. J Porous Mater 2011; 18: 715–721.

15.

Barzegari

Yao

Rodrigue

. Mechanical properties of density graded foams: tensile properties. Cell Polym 2013; 32: 323–341.

16.

Liu

Huang

. Dynamic analysis of functionally graded porous structures through finite element analysis. Eng Struct 2018; 165: 287–301.

17.

Niknam

Akbarzadeh

Rodrigue

. Architected multi-directional functionally graded cellular plates, materials and design. Mater Design 2018; 148: 188–202.

18.

Chen

. Mitigating performance of elastic graded polymer foam coating subjected to underwater shock. Compos B Eng 2015; 69: 484–495.

19.

De Marco Muscat-Fenech

Cortis

Cassar

. Impact damage testing on composite marine sandwich panels. Part 2: instrumented drop weight. J Sand Struct Mater 2014; 16: 443–480.

20.

Kavianiboroujeni

Cloutier

Rodrigue

. Low velocity impact behavior of asymmetric three-layer sandwich composite structures with and without foam core. Polym Compos 2017; 25: 381–393.

21.

Barzegari

Rodrigue

. Flexural behavior of asymmetric structural foams. J Appl Polym Sci 2009; 113: 3103–3112.

22.

Ramirez

Misra

Gupta

. Viscoelastic foam-filled lattice for high energy absorption. Mech. Mater 2018; 127: 39–47.

23.

Cui

Kiernan

Gilchrist

. Designing the energy absorption capacity of functionally graded foam materials. Mater Sci Eng A 2009; 507: 215–225.

Density graded polyethylene foams: Effect of processing conditions on mechanical properties

Abstract

Keywords

Get full access to this article

References