ADDITIVES | THERMALLY CONDUCTIVE
Graphene-LDPE Blend
G3 has its own in-house melt-blending expertise and has already produced compounds based on various polymers, including PP, LDPE, HDPE, LLDPE, ABS, PLA, polyamides, and TPEs as well as PC/ABS films (Figure 7).
Graphene-HDPE Blend
Effective dispersion Avanzare Innovacion Tecnologica describes its avanThermal Conductive 770 as a graphene-relat- ed black designed for effective dispersion in a broad range of thermoplastics. It is said to be easy to integrate in different formulae; recommended dosage ranges from 1 to 12% depending on the matrix and thermal conductivity target. The average particle size is about 70 microns and thickness less than 8 nm. Oxygen content is said to be very low (less than 1%) as is the level of defects. “It is important to highlight the influence on the
Figures 5 (top) and 6: Graphene can improve thermal conductivity and modulus in LDPE and HDPE compounds. Blending behaviour is different in the two polymers, however, due to differences in crystallinity Source: Global Graphene Group
Graphene-ABS/PC Blend
results, not only of the matrix particularities itself, but also the processing method and conditions,” Avanzare says. Used in polypropylene, avanTher- mal Conductive 770 raised thermal conductivity by about 200% over the unfilled PP grade (also enhancing electrical conductivity over 1 S/m). Injection moulded PA6 specimens showed an increase in thermal conductivity of about ten times (Figure 8, page 28). Avanzare says even higher thermal conductivity (more than 3 W/m.K) can be achieved using a specially modified avanThermal Conductive 770. Illustrating the influence of the matrix resin on
the results obtained, the effect of addition of avanThermal Conductive770 on thermal conductiv- ity of PEEK is rather different (Figure 9, page 28). Staying with carbon, but in another of its many
Figure 7: Data from tests on films of PC/ABS filled with different amounts of graphene show how heat dissipation increases with filler loading (the film is heated from below and a steady-state temperature measured at a fixed distance above it) Source: Global Graphene Group
various ways: for example, to improve its compat- ibility with the matrices it is intended to be used in. Speaking at Conductive Plastics USA, Chan pointed out that it is possible to achieve high loadings of graphene in thermoplastics – as high as 50% and possibly higher – creating materials with thermal conductivities several times higher than the unfilled polymer (Figures 5 and 6). Compounds with such high loadings would normally be used as masterbatches.
26 COMPOUNDING WORLD | April 2018
variants, nanodiamond manufacturer Carbodeon has teamed up with Dutch 3D printing specialist Tiamet 3D to launch nanodiamond-enhanced filaments. They are based on a jointly-patented technology which is said to significantly improve the mechanical and thermal properties of 3D printed items. “We’ve already developed filaments with a 100%
increase in tensile strength, improved printability, and better thermal properties,” says Reid Larson, CEO of Tiamet 3D. “Printing also runs more quickly and more reliably.” The two partners say 3D printing using im-
proved-performance thermoplastics has potential in almost all manufacturing environments, but especially in electronics, automotive and aerospace industries. They say that as well as improving thermal management, conductivity and tensile strength of the base polymer, nanodiamonds can increase the glass transition temperature of the end
www.compoundingworld.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94
