Chemistry, asked by sahanapatil7409, 1 year ago

Hummers method for graphene oxide synthesis

Answers

Answered by snehanair
0

Product 1.2 from previous lists has been replaced by Product 1.2A below.

 

Product 1.2A: HCl-free 25 % aqueous paste: 25 % GO, 75 % water. This product has been first dried and then re-dispersed in de-ionized water. This GO is a solid acid with about 1.3 mmol total acidity per gram. Total acidity is the sum of acidic functional groups and adsorbed acids (HCl and H2SO4). When diluted to 0.1 weight % the suspension has a PH of about 2.9.

Product code

Amount of GO

Form

Amount of paste

Price (USD)

1.2A/10Kg

2.5 Kg

Aqueous paste

10 Kg

5000

1.2A/4Kg

1 Kg

Aqueous paste

4 Kg

2200

1.2A/1Kg

0.25 Kg

Aqueous paste

1 Kg

  900

1.2A/0.4Kg

0.1 Kg

Aqueous paste

400 g

  450

1.2A/0.1Kg

25 g

Aqueous paste

100 g

  125

 

 

Product 1.3: Water-washed 25 % aqueous GO paste: 25 % GO, 75 % water. This product has been washed with water to reduce acidity. This GO-product is a weak solid acid with about 0.4 mmol acid sites/g.  When diluted to 0.1 weight % the suspension has pH about 4 when packed. The product is perfectly dispersible in de-ionized water using ultra-sound bath for 1/2 h. However, if dried, it can not be re-dispersed, so if dispersing is required, do not dry!

Product code

Amount of GO

Form

Amount of paste

Price (USD)

1.3/10Kg

2.5 Kg

Aqueous paste

10 Kg

6000

1.3/4Kg

1 Kg

Aqueous paste

4 Kg

2800

1.3/1Kg

0.25 Kg

Aqueous paste

1 Kg

1200

1.3/0.4Kg

0.1 Kg

Aqueous paste

0.4 Kg

  550

1.3/0.1Kg

25 g

Aqueous paste

100 g

  150

 

 

Product 1.4: Water-washed 10 % aqueous GO paste: 10 % GO, 90 % water. This product has been washed extensively with de-ionized water to reduce acidity. This GO-product is a weak solid acid with about 0.4 mmol acid sites/g, and slightly less than product 1.3. When diluted to 0.1 weight % the suspension has pH > 4 when packed. The product is perfectly dispersible in de-ionized water using ultra-sound bath for 1/2 h. However, if dried, it can not be re-dispersed, so if dispersing is required, do not dry!

Product code

Amount of GO

Form

Amount of paste

Price (USD)

1.4/25Kg

2.5 Kg

Aqueous paste

25 Kg

6200

1.4/10Kg

1 Kg

Aqueous paste

10 Kg

2900

1.4/2.5Kg

0.25 Kg

Aqueous paste

2.5 Kg

1250

1.4/1Kg

0.1 Kg

Aqueous paste

   1 Kg

  600

1.4/0.25Kg

25 g

Aqueous paste

250 g

  175

 

 

 

Product 1.5: Water washed aqueous GO paste or suspension of any concentration / any pH according to customers’ needs.  Please enquire for quote.

 

 

Product 1.6: Freeze dried GO. This product is prepared in two forms. Either by dropping 2 % or 5 % suspension of GO into liquid N2 with subsequent freeze drying in the form of beads, or by freezing wet films with liquid N2 with subsequent freeze drying and mechanical disintegration to form powder. Can optionally be prepared from products 1.2A, 1.3 or 1.4.

Answered by nostalgicanshuman
0


Abstract

The aim of this study is to study the influence of different solvents on the structure and electrical properties of graphene oxide. GO was obtained from graphite flakes by using modified hummers method in which different from conventional hummer's method. In this method, the experiment was synthesized without sodium nitrate (NaNO3) and ice bath, but carried out at room temperature. Prepared GO powders were then dissolved into different solvents, namely acetone and ethanol. Then spin-coated onto silicon wafer and IDE to produce acetone-GO (A-GO) and ethanol-GO (E-GO). SEM result shows that several square micron GO were obtained. In addition, due to the large agglomerates and contact between the flakes in E-GO sample, current-voltage pattern indicated the E-GO produced higher current flow than A-GO. Meanwhile, GO characterized using FTiR shows that both samples contain several functional groups such as hydroxyl, epoxy, carboxyl and carbonyl. Besides that, due to the lower diffraction peak of A-GO, XRD result shows the interlayer spacing of A-GO sample is slightly higher than E-GO sample.

OR

Abstract

Processing conditions are one of the factors that significantly influences the properties and characteristics of the polymer matrix composites products. Therefore, the suitable processing parameters must be selected in order to yield the optimum properties of the composite products. In this work, Box-Behnken Design (BBD) was selected as experimental design approach. Biodegradable composites from unidirectional long kenaf fibre reinforced polylactic-acid were fabricated by hot pressing method. Response surface methodology (RSM) and analysis of variance (ANOVA) were used to optimize as well as determine the significance of the factors affecting the tensile strength. Three factors studied were pressure, temperature and heating time at three different levels. The experimental results showed that all three factors are the significant processing parameters affecting the strength of composite. The combination of hot pressing parameters for optimum tensile strength was 200oC temperature, 3MPa pressure, and heating time at 8 minutes. Confirmation runs test yield error less than 7% verified the validity of the model.


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