Insights into Phosphorus-Containing Flame Retardants …
235
1.3 Organic or Organophosphorus-Based FRs
Organophosphorus-based FRs gain increased attention preventing the risks of fire in
recent times because of their significant efficacy and environmentally safer nature
over halogenated and formaldehyde containing FRs [30]. Organophosphorus FRs
have been used from last few decades and widely used for several various polymeric consumer products like plastics, textiles, polyurathanes (PU), polyamides (PA),
polyethyleneterephthalate (PET), epoxy-materials etc. [31, 32]. Organophosphorus
compounds containing P–C bonds are developed extensively as FR additives due to
their excellent thermal and hydrolytic stability as well as ease of generation. In a
mechanistic pathway it was observed that during the fire, phosphorus compounds
break down to phosphorus acid which blocks polymer’s oxygen functionality, and
therefore lead to the char-formation in the high ratio [33].
Wendels et al. [34] has published an exhausted and comprehensive review on
organophosphorus compounds for the recent developments in organophosphorus
flame retardants (OPFRs) having P–C bonding with their synthesis pathways and
applications [34].
Nowadays, various products, large in numbers are commercially available based
on organophosphorous compound. On the basis of carbon unit/moiety OPFRs can
be broadly categorized into five main classes (Table 1) [17, 32–36]:
(i) organophosphates,
(ii) organophosphonates,
(iii) organophosphinites,
(iv) organoposphine oxide, and
(v) organophosphites.
1.3.1 Organophosphate FRs
Organophosphate FRs with a wide range in their polarity, solubility and persistence
have been produced and used as significant FRs in substitutes to the stringent regulation in the use of brominated FRs. These FRs are widely used as flame retardants
in various consumer products such as textiles, electronics, industrial materials and
furniture to prevent the high risk of fire [1, 32]. A large number of OPFRs have
been fabricated with varied P–C assemblies. Some commonest OPFRs are shown in
Table 1.
Aliphatic: P–C aliphatic bond containing organophosphorus compounds have been
utilized as good FRs to polymeric materials such as Dimethyl phosphate (DMP),
Diethyl phosphate (DEP), Trimethyl phosphate (TMP), Tripropyl phosphate (TPP),
Tri-isopropyl phosphate (TIPP), Tri-n-butyl phosphate (TNBP) Tris(2-butoxyethyl)
phosphate (TBOEP) etc.
Cl-aliphatic: Chlorine-based P–C aliphatic bond containing organophosphorus compounds have superior flame retardancy. Examples of this subclass include
235
1.3 Organic or Organophosphorus-Based FRs
Organophosphorus-based FRs gain increased attention preventing the risks of fire in
recent times because of their significant efficacy and environmentally safer nature
over halogenated and formaldehyde containing FRs [30]. Organophosphorus FRs
have been used from last few decades and widely used for several various polymeric consumer products like plastics, textiles, polyurathanes (PU), polyamides (PA),
polyethyleneterephthalate (PET), epoxy-materials etc. [31, 32]. Organophosphorus
compounds containing P–C bonds are developed extensively as FR additives due to
their excellent thermal and hydrolytic stability as well as ease of generation. In a
mechanistic pathway it was observed that during the fire, phosphorus compounds
break down to phosphorus acid which blocks polymer’s oxygen functionality, and
therefore lead to the char-formation in the high ratio [33].
Wendels et al. [34] has published an exhausted and comprehensive review on
organophosphorus compounds for the recent developments in organophosphorus
flame retardants (OPFRs) having P–C bonding with their synthesis pathways and
applications [34].
Nowadays, various products, large in numbers are commercially available based
on organophosphorous compound. On the basis of carbon unit/moiety OPFRs can
be broadly categorized into five main classes (Table 1) [17, 32–36]:
(i) organophosphates,
(ii) organophosphonates,
(iii) organophosphinites,
(iv) organoposphine oxide, and
(v) organophosphites.
1.3.1 Organophosphate FRs
Organophosphate FRs with a wide range in their polarity, solubility and persistence
have been produced and used as significant FRs in substitutes to the stringent regulation in the use of brominated FRs. These FRs are widely used as flame retardants
in various consumer products such as textiles, electronics, industrial materials and
furniture to prevent the high risk of fire [1, 32]. A large number of OPFRs have
been fabricated with varied P–C assemblies. Some commonest OPFRs are shown in
Table 1.
Aliphatic: P–C aliphatic bond containing organophosphorus compounds have been
utilized as good FRs to polymeric materials such as Dimethyl phosphate (DMP),
Diethyl phosphate (DEP), Trimethyl phosphate (TMP), Tripropyl phosphate (TPP),
Tri-isopropyl phosphate (TIPP), Tri-n-butyl phosphate (TNBP) Tris(2-butoxyethyl)
phosphate (TBOEP) etc.
Cl-aliphatic: Chlorine-based P–C aliphatic bond containing organophosphorus compounds have superior flame retardancy. Examples of this subclass include