Graphene has many amazing properties and it is believed that graphene will be the material for next generation electronic semiconductors to substitute silicon. Generally, conductive carbon black is used extensively to increase polymer conductivity-the main drawback is that the mechanical properties of carbon black-filled polymer composites decrease due to the high level of inorganic filler used. However, high polymer conductivity is noticed in graphene. How to harness these unique properties of graphene in real-world industry is a challenge.
Types of graphene
Graphene materials come in four different types: single-layer graphene (have one carbon layers), bi–layer graphene (have two carbon layers), few-layer graphene (have 3-10 carbon layers), and graphene nanoplatelets (more than ten carbon layers, but the platelet thickness is less than 100 nanometre). Graphene nanoplatelets have high aspect ratio (width–to–thickness) in structure feature which helps to form the conducting network in a polymer matrix. Graphene sheets are prepared by chemical routes, such as the method involving oxidation of graphite to produce graphite oxide and then reduction of the graphene oxide into graphene.
Graphene production
To meet real-world applications graphene materials, especially the single-layer, double- and few-layer graphene, need to be produced on a large scale with a controlled quality and low cost. The mass production of single- and bi-layer graphene seems still a great challenge, especially with a high crystal quality and controlled layers. However, large scale production of graphene nanoplatelets is not so difficult.
Production in China
Chinese company Xiamen Knano Graphene Technology Co.,Ltd. (www.knano.com.cn) has developed a proprietary industry route to produce nanoplatelets on large scale. These products have a high crystal degree, and therefore will exhibit higher electrical and thermal conductivity and mechanical performance.
The company is the first in mainland China involved in mass production and applications development of graphene nanoplatelets. It started research and development of grapheme with Dr. Guohua Chen and his Huaqiao University team in 2006, and became a registered company in May 2010. In October 2010, The Royal Swedish Academy of Sciences awarded the Nobel Prize in Physics for 2010 to Andre Geim and Konstantin Novoselov, both of the University of Manchester, “for groundbreaking experiments regarding the two-dimensional material graphene.”
On July 30th, 2013, Knano and Zhongtai Chemical announced that the two companies had entered into an agreement to create a strategic partnership. Under the agreement, the two companies agreed to begin joint development of graphene / Polyvinylchloride products for industries. Knano are pouring huge sums into science, particularly at the applied end of graphene. So far, it cooperates with hundreds of customers for providing productions as end-use applications.
Knano supplies graphene, graphene oxide, Graphene nanoplatelets and other products used as electric and thermal conductive fillers. Their KNG series graphene nanoplatelets are low-cost multi-functional nano-additives in composite to improve mechanical performance, thermal conductivity and stability, and electrical conductivity. The company has the capacity for the industry–scale production of graphene and graphene nanoplatelets.
The graphene KNG-G5 is a newly developed graphene product which consists of large numbers of single-layer sheets and a few-layer graphenes having a high aspect ratio. The production process involves no oxidation and reduction treatment, therefore the crystal structure of six-numbered-ring plane in graphene is well preserved, giving an excellence electrical conductivity and stability.
Source: Johnson Fung, Assistant General Manager, Xiamen Knano Graphene Technology CO., LTD. Tel:+86 5922684582, Email: cqfang@knano.com.cn. Website: www.knano.com.cn
