Table 1.

A brief record of epoxy-based nanocomposites studied for improvement in fracture toughness values.

Sr.	Authors	Year	Reinforcement/(wt %)		Dispersion method	% Increase in K1C (MPa·m1/2)	Remarks	Ref.
1	Wan et al.	2014	GO (0.25 wt %)		Sn + BM	25.6	K1C drops after 0.25 wt % of reinforcement	[63]
			DGEBA-f-GO (0.25 wt %)			40.7
2	Sharmila et al.	2014	MERGO (0.25 wt %)		MS + USn	63	K1C drops after 0.25 wt % of reinforcement	[64]
3	Zhang et al.	2014	GnPs (0.5 wt %)		Sn	27.6	Trend still increasing	[65]
			fGnPs (0.3 wt %)			50.5	K1C drops after 0.3 wt % of reinforcement
4	Moghadam et al.	2014	UG (0.5 wt %)		3RM	55	K1C drops after 0.5 wt % of reinforcement	[66]
			GO (0.5 wt %)			57
			G-NH2 (0.5 wt %)			86
			G-Si (0.5 wt %)			86
5	Ma et al.	2014	m-GnP (1 wt %)		MS + Sn	131	K1C drops after 1 wt % of reinforcement of m-GnP	[59]
6	Chandrasekaran et al.	2014	TRGO (0.5 wt %)		3RM	44.5	Trend still increasing	[67]
			GNP (1 wt %)			49	K1C drops after 1 wt %
			MWCNTs (0.5 wt %)			12.7	Trend still increasing
7	Wan et al.	2014	GO (0.1 wt %)		Sn + BM	24	K1C improves with silane functionalization	[68]
			Silane-f-GO (0.1 wt %)			39
8	Zaman et al.	2014	m-clay (2.5 wt %)		MS	38	K1C drops after 2.5 wt % m-clay	[69]
			m-GP (4 wt %)			103	Trend still increasing
9	Jiang et al.	2014	SATPGO (0.5 wt %)		USn	92.8	K1C drops after 0.5 wt % of reinforcement	[70]
10	Shokrieh et al.	2014	GPLs (0.5 wt %)		Sn	39	K1C drops after 0.5 wt % of reinforcement	[71]
			GNSs (0.5 wt %)			16
11	Jia et al.	2014	GF (0.1 wt %) (resin infiltration)		None	70	K1C did not change much between 0.1 to 0.5 wt %	[58]
12	Tang et al.	2013	Poorly dispersed RGO (0.2 wt %)		Sn	24	Trend still increasing	[72]
			Highly dispersed RGO (0.2 wt %)		Sn + BM	52
13	Wang et al.	2013	GO	10.79 µm (0.5wt %)	USn	12	K1C drops after 0.5 wt % of reinforcement	[57]
				1.72 µm (0.5 wt %)		61
				0.70 µm (0.1 wt %)		75
14	Chandrasekaran et al.	2013	GNPs* (0.5 wt %)		3RM	43	Dispersion and K1C improved with three roll milling	[73]
15	Li et al.	2013	APTS-GO (0.5 wt %)		USn	25	Trend still increasing	[74]
			GPTS-GO (0.2 wt %)			43	K1C drops after 0.2 wt % of reinforcement
16	Shadlou et al.	2013	ND (0.5 wt %)		USn	No effect	Fracture toughness improvement is higher by CNF and GO (high aspect ratio) compared with that by spherical ND	[75]
			CNF (0.5 wt %)			4.3
			GO (0.5 wt %)			39.1
17	Jiang et al.	2013	GO (0.1 wt %)		Sn	31	Trend remains same after 1 wt % of reinforcement	[76]
			ATS (1 wt %)			58.6	K1C drops after 0.1 wt % of reinforcement
			ATGO (1 wt %)			86.2	The maximum improvement is achieved with functionalization
18	Liu et al.	2013	p-CNFs (0.4 wt %)		Sn	41	Trend still increasing	[77]
			m-CNFs (0.4 wt %)			80
19	Wang et al.	2013	ATP (1 wt %)		Sn	14	K1C drops after 0.1 wt %	[78]
			GO (0.2 wt %)			19	Trend still increasing after 0.2 wt %
			ATP (1 wt %) + GO (0.2 wt %)			27	K1C drops with the further increase in ATP of reinforcement
20	Alishahi et al.	2013	ND (0.5 wt %)		Sn	−26.9	Trend still increasing	[79]
			CNF (0.5 wt %)			19
			GO (0.5 wt %)			23
			CNT (0.5 wt %)			23.8
21	Ma et al.	2013	U-GnP (0.5 wt %)		MgSr + USn	49	Trend still increasing	[80]
			m-GnP (0.5 wt %)			109
22	Feng et al.	2013	Graphene (0.5 wt %)		Sn	76	K1C decreases after 0.5 wt % of reinforcement	[81]
23	Chatterjee et al.	2012	GnPs (5 µm, 2 wt %)		3RM	60	Trend still increasing	[82]
			GnPs (25 µm, 2 wt %)			80
			CNTs (2 wt %)			80
			CNT:GnP = (9:1) (2 wt %)			76
24	Chatterjee et al.	2012	EGNPs (0.1 wt %)		HPH + 3RM	66	K1C drops after 0.1 wt % of reinforcement	[83]
25	Zaman et al.	2011	GP (2.5 wt %)		Sn + MS	57	The surface modification significantly improved the K1C	[84]
			m-GP (4 wt %)			90
26	Rana et al.	2011	CNFs		Sn + MS	40	K1C is dependent upon mixing time	[85]
27	Bortz et al.	2011	GO (0.5 wt %)		3RM	60	K1C drops after 0.5 wt % of reinforcement	[86]
28	Zhang et al.	2010	CNFs (0.5 wt %)		3RM	19.4	Trend still increasing	[87]
			SCFs (15 wt %)			125.8
			SCF (10 wt %)/CNF (0.75 wt %)			210
29	Fang et al.	2010	GNs		MS + Sn	93.8	Better results with combination of MS and Sn	[88]
30	Jana et al.	2009	GP with “puffed” structure (5 wt %)		Sn	28	Trend still increasing	[89]
31	Rafiee et al.	2009	SWNT (0.1 wt %)		Sn + MS	17	Graphene platelets have more influence on K1C than CNTs	[90]
			MWNT (0.1 wt %)			20

3RM: three roll milling; APTS-GO: amino-functionalized graphene oxide (GO); ATGO: 3-Aminopropyltriethoxysilane functionalized silica nanoparticles attached GO; ATP: attapulgite; ATS: 3-amino functionalized silica nanoparticles; BM: ball milling; CNF: carbon nanofiber; CNT: carbon nanotube; DGEBA-f-GO: diglycidyl ether of bisphenol-A functionalized GO; EGNP: amine functionalized expanded graphene nanoplatelets; fGnP: polybenzimidazole functionalized graphene platelets (GnPs); G-NH2: amino-functionalized GNPs; G-Si: silane modified GNPs; GF: graphene foam; GN: amine functionalized graphene sheet; GnP: graphene platelet; GNP*: graphite nanoplatelet; GNS: graphene nanosheet; GO: graphite; GP: graphite particles; GPL: graphene nanoplatelets; GPTS-GO: epoxy functionalized GO; HPH: high pressure homogenizer; m-clay: surface modified nano clay; m-CNF: triazole functionalized carbon nanofiber; m-GnP: surface modified GnP; m-GnP*: surfactant modified graphene platelet; m-GP: surface modified graphene platelets; MERGO: microwave exfoliated reduced graphene oxide; MgSr: magnetic stirring; MS: mechanical stirring; MWCNT: multi-walled carbon nanotube; MWNT: multi-walled carbon nanotubes; ND: nanodiamond; pCNF: pristine carbon nanofibers; RGO: thermally reduced graphene oxide; SATPGO: 3-aminopropyltriethoxysilane modified silica nanoparticles attached GO; SCF: short carbon fibers; Silane-f-GO: silane functionalized GO; Sn: Sonication; SWNT: single-walled carbon nanotubes; U-GnP: unmodified graphene platelets; UG: unmodified graphene nanoplatelets; USn: ultrasonication.