Gas permeability of melt-processed poly(ether block amide) copolymers and the effects of orientation

Armstrong, Shannon R.; Freeman, Benny D.; Hiltner, A.; Baer, E.

doi:10.1016/j.polymer.2012.01.037

Cited by 80 publications

(108 citation statements)

References 33 publications

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“…Strain-induced crystallization of PTMO severely restricts diffusion of gas through the SS leading to a decrease in gas permeation. [42] Another application for PEBA block copolymers receiving attention recently is use as antistatic agents. Wang et al recently published a report on the blending of acrylonitrile-butadiene-styrene (ABS) resin with a PEBA composed of PTMO/nylon-6 to impart antistatic properties to the blended material.…”

mentioning

confidence: 99%

Amide-containing segmented copolymers

Buckwalter

Dennis

Long

2015

Progress in Polymer Science

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mentioning

confidence: 99%

Amide-containing segmented copolymers

Buckwalter

Dennis

Long

2015

Progress in Polymer Science

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“…It consists of 80% hard segments of polyamide-12 (PA12) and 20% soft segments of poly (tetramethylene oxide) (PTMO) by molecular weight [27]. Microinjection molding experiments were carried out using a Fanuc Roboshot S-2000i 15B reciprocating microinjection molding machine, equipped with an injection screw with a diameter of 14mm.…”

Section: Materials and Processing Conditionsmentioning

confidence: 99%

“…Autodesk Moldflow Insight (AMI) was used to simulate the polymer filling process of the dumbbell part (see Figure 1 (c)). Since there is no Pebax 7233 data in the AMI database, we used Pebax 7033 data instead, which has 75% PA12 and 25% PTMO by molecular weight, similar to 7233 [27]. The profile of screw speed vs. time during filling stage, and packing pressure vs. time during the packing stage of the injection-molding machine from the corresponding experiments were monitored using in-line process monitoring, as described in our previous work [10], and they are manually input into AMI to reflect real molding characteristics that are as realistic and precise as possible.…”

Section: Numerical Simulationmentioning

confidence: 99%

Effects of gate design and cavity thickness on filling, morphology and mechanical properties of microinjection mouldings

Zhang

Choi

et al. 2015

Materials & Design

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Miniaturized parts weighing single or tens of milligrams represent a large category of microinjection moulded products. Both miniaturization and extreme processing under microinjection moulding subject material to high shear rates and high cooling rates, and cause the same material to have different morphologies and final properties when used in conventional injection moulding. It also makes mold design challenging. This study investigates the effects of micro gate design (opening and thickness) and cavity thickness (100-500μm) on filling, morphology and the mechanical properties of miniaturized dumbbell parts. It is found that a reduction of gate size has two conflicting effects, namely, increased shear heating increases flow length, and increased cooling rate reduces flow length. Filling increases significantly with an increase of cavity thickness. In addition, the thickness of the skin layer reduces from ~70% to ~10% when part thickness increases from 100μm to 500μm. This oriented skin layer determines molecular orientation and broadly influences Young's modulus, elongation and yield stress. Natural aging at room temperature induces an increase of modulus and yield stress, and a decrease of strain at break. The mechanical properties of microinjection moldings is significantly different from those of conventional injection moldings and measurement at microscale is required for miniaturized product design. 1 Effect of Gate Design and AbstractMiniaturized parts weighing single or tens of milligrams represent a large category of microinjection moulded products. Both miniaturization and extreme processing under microinjection moulding subject material to high shear rates and high cooling rates, and cause the same material to have different morphologies and final properties when used in conventional injection moulding. It also makes mold design challenging. This study investigates the effects of micro gate design (opening and thickness) and cavity thickness (100-500μm) on filling, morphology and the mechanical properties of miniaturized dumbbell parts. It is found that a reduction of gate size has two conflicting effects, namely, increased shear heating increases flow length, and increased cooling rate reduces flow length.Filling increases significantly with an increase of cavity thickness. In addition, the thickness of the skin layer reduces from ~70% to ~10% when part thickness increases from 100μm to 500μm. This oriented skin layer determines molecular orientation and broadly influences Young's modulus, elongation and yield stress. Natural aging at room temperature induces an increase of modulus and yield stress, and a decrease of strain at break. The mechanical properties of microinjection moldings is significantly different from those of conventional injection moldings and measurement at microscale is required for miniaturized product design.

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“…PEBA resins were purchased from Arkema Technical Polymers (Colombes, France). Hydrophobic Pebax 2533 is composed of 80% polytetramethylene oxide and 20% polyamide, whereas hydrophilic Pebax MH 1657 contained 60% of polyether block segment [16,17]. The resins were dried in an oven at 60-70˚C before use and were stored in a desiccator.…”

Section: Membrane Preparationmentioning

confidence: 99%

Partial nitrification in a membrane-aerated biofilm reactor with composite PEBA/PVDF hollow fibers

Nisola

Orata-Flor

et al. 2013

Desalination and Water Treatment

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A B S T R A C TAmmonia removal via nitrite was performed in membrane-aerated biofilm reactors (MABR). Two types of hollow fiber (HF) modules, uncoated microporous polyvinylidene fluoride (PVDF) and composite polyether-block-polyamide copolymer (PEBA) coated PVDF, were used as supports for the growth of ammonia oxidizing microorganism biofilm system. For the composite HF, a suitable coating material was selected between hydrophilic and hydrophobic types of PEBA. Results reveal that hydrophobic PEBA 2533 was more suitable for bacterial adhesion. The formation of coating layer was successfully confirmed through field emission scanning electron microscope. Other surface characterizations were performed through atomic force microscopy and contact angle measurements. Partial nitrification experiments at varied feed concentrations and hydraulic retention times reveal that MABR with uncoated PVDF HF exhibited slightly higher ammonia removal than the MABR with composite HF. In terms of nitrified products, MABR with composite HF produced > 90% of the removed ammonia in nitrite form. On the other hand, around 50% of nitrite was converted to nitrate in the MABR with uncoated PVDF. Thus, between the two membranes tested, PEBA 2533 coated PVDF is the more suitable HF for ammonia removal via nitrite formation in the MABR system.

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Gas permeability of melt-processed poly(ether block amide) copolymers and the effects of orientation

Cited by 80 publications

References 33 publications

Amide-containing segmented copolymers

Amide-containing segmented copolymers

Effects of gate design and cavity thickness on filling, morphology and mechanical properties of microinjection mouldings

Partial nitrification in a membrane-aerated biofilm reactor with composite PEBA/PVDF hollow fibers

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