Flame retardant impact modifier

Noryl. Noryl engineering thermoplastics are polymer blends formed by melt-blending DMPPO and HIPS or other polymers such as nylon with proprietary stabilizers, flame retardants, impact modifiers, and other additives (69). Because the mbber characteristics that are required for optimum performance in DMPPO—polystyrene blends are not the same as for polystyrene alone, most of the HIPS that is used in DMPPO blends is designed specifically for this use (70). Noryl is produced as sheet and for vacuum forming, but by far the greatest use is in pellets for injection mol ding. 

Table 6. Flame Retarding Impact Modified 2/1 Polycarbonate/PET Blend...

The dynamic mechanical behavior of most homogeneous and heterogeneous solid and molten polymeric systems or composite formulations can be determined by DMA. These polymeric systems may contain chemical additives, including fillers, reinforcements, stabilizers, plasticizers, flame retardants, impact modifiers, processing aids, and other chemical additives, which are added to the polymeric system to impart specific functional properties and which could affect the process-ability and performance. 

Performance of other additives Fillers arc instrumental in improving the performance of other additives. Antistatics, blowing agents, catalysts, compatibilizers, coupling agents, organic flame retardants, impact modifiers, rheology modifiers, thermal and UV stabilizers are all influenced by a fillet s presence. 

Flame Retardants Impact Modifiers Lubricants and Processing Aids... 

Noryl. Noiyl engineering thermoplastics are polymer blends formed by melt-blending DMPPO and HIPS or other polsrmers such as nylon with proprietary stabilizers, flame retardants, impact modifiers, and other additives (75). Because the rubber characteristics that are required for optimiun performance in... 

Solid-state NMR has been widely employed for problems related to flame retardants, impact modifiers, plasticisers (and plasticiser motion), fillers (including polymer-filler interactions), co-polymers, grafting, elastomers and filled vulcan-isates, molecular symmetry and heterogeneity, etc. Use of NMR is recommended particularly for insoluble components (such as high-MW species) at high levels (typically >1%). Obviously, direct NMR of polymers suffers from matrix interference of the polymer carbon backbone yielding complex spectra. Therefore, studies on polyolefins and PVC are relatively favoured, whereas polyacrylates are unfavoured. (SPE and CP/MAS) NMR and in situ NMR were used in a study of PU/melamine [676],... 

Low-field low-resolution NMR is extensively being used both for process and quality control of polyolefins [198] and blends e.g. ABS/PC), but less so for additive dosing and monitoring. LR-NMR has limited use for polymer/additive analysis. If any, given the detection limits, LR-NMR is most suited for additives present in relatively high percentage levels such as plasticisers, flame retardants, impact modifiers, fillers, or lubricants, and does not reveal antioxidants, UV stabilisers, etc. 

Blowing agents, flame retardants, impact modifiers, processing aids, stabilizers, LTV absorbers, antistatic agents, pigments... 

Figure 6.87 Tensile stress amplitude versus cycles to failure at 23°C of SABIC Innovative Plastics Valox 368— flame-retardant, impact-modified, mold release PBT/PC alloy [3]. 

The clarity, toughness and barrier properties make PET best suited for its primary market - blow-moulded carbonated soft drinks containers. Speciality grades include flame retardant, impact modified and glass, mineral, carbon, PTFE and mica filled. 

Modified-polyphenylene oxide (or ether) is a blend of high impact polystyrene (PS) and polyphenylene oxide (PPO), plus thermal stabilizers and a triarylphosphate flame retardant. Studies of the mechanism of the flame retardant in modified-polyphenylene oxide have shown some evidence for both solid phase and vapor phase inhibition (4). Indeed, one is always interested to know whether flame retardant action is on the solid or vapor phase. 

Poly(vinyl chloride). PVC is one of the most important and versatile commodity polymers (Table 4). It is inherently flame retardant and chemically resistant and has found numerous and varied appHcations, principally because of its low price and capacity for being modified. Without modification, processibiUty, heat stabiUty, impact strength, and appearance all are poor. Thermal stabilizers, lubricants, plasticizers, impact modifiers, and other additives transform PVC into a very versatile polymer (257,258). 

Blends of ABS with polycarbonates have been available for several years (e.g. Bayblend by Bayer and Cycoloy by Borg-Wamer). In many respects these polymers have properties intermediate to the parent plastics materials with heat distortion temperatures up to 130°C. They also show good impact strength, particularly at low temperatures. Self-extinguishing and flame retarding grades have been made available. The materials thus provide possible alternatives to modified poly(phenylene oxides) of the Noryl type described in Chapter 21. (See also sections 16.16 and 20.8.)... 

A large number of grades is available, one supplier alone offering about 40, including unreinforced, glass- and carbon-fibre reinforced, mineral filler reinforced, impact modified, elastomer modified, flame retardant and various combinations of the foregoing. 

Impact energy can be further improved by the use of impact modifiers. In this approach the combination of impact improvement and fire retardant enhancing is of special interest (ref. 5). Figure 5 demonstrates this effect in ABS flame-retarded with commercial FR-1208 (octabromodiphenyl oxide) and with the proprietary FR-T6385. 

Phosphorus -bromine flame retardant synergy was demonstrated in a 2/1 polycarbonate/polyethylene blend. These data also show phosphorus to be about ten times more effective than bromine in this blend. Brominated phosphates, where both bromine and phosphorus are in the same molecule, were also studied. In at least one case, synergy is further enhanced when both phosphorus and bromine are in the same molecule as compared with a physical blend of a phosphorus and a bromine compound. On a weight basis, phosphorus and bromine in the same molecule are perhaps the most efficient flame retardant combination. The effect of adding an impact modifier was also shown. 

A 2/1 blend of polycarbonate and polyethylene terephthalate (PC/PET) was flame retarded with bromine, phosphorus, a blend of bromine and phosphorus, and compounds containing both phosphorus and bromine in the same molecule. All compositions contained 0.5 % Teflon 6C as a drip inhibitor and where specified 5 % of an impact modifier. 

Table 6 shows the flamability characteristics of an impact modified 2/1 polycarbonate/PET blend containing 6 % of the various flame retardants. The composition containing the brominated phosphate 60/4 is the only one which is V-0 by the UL-94 vertical burn test. At 10 % add-on, the all-bromine containing resin is V-1 and at 13 % add-on the all-phophorus containing resin is V-0. 

Worldwide consumption of performance additives (excluding plasticisers) grew from just over 2.7 mt in 1996 to 3.6 mt in 2001. Flame retardants make up 31 % of the volume and stabilisers, impact modifiers and lubricants each account for around 16-17%. Flame retardant markets (construction, E E devices, automotive) are headed for unprecedented development and change, being threatened by environmental, health... 

Various additives show considerable extraction resistance, such as impact modifiers (polyacrylates and polyblends PVC/EVA, PVC/ABS, etc.), highpolymeric processing aids (PMMA-based), elastomers as high-MW plasticisers, reactive flame retardants (e.g. tetrabromobisphenol-A, tetrabromophthalic anhydride, tetrabromophthalate diol, dibromostyrene). Direct measurement of additives by UV and IR spectroscopy of moulded films is particularly useful in analysing for additives that are difficult to extract, although in such cases the calibration of standards may present a problem and interferences from other additives are possible. 

Hydrolysis of polyamide-based formulations with 6 N HC1 followed by TLC allows differentiation between a-aminocaproic acid (ACA) and hexamethylenedi-amine (HMD) (hydrolysis products of PA6 and PA6.6, respectively), even at low levels. The monomer composition (PA6/PA6.6 ratio) can be derived after chromatographic determination of the adipic acid (AA) content. Extraction of the hydrolysate with ether and derivatisa-tion allow the quantitative determination of fatty acids (from lubricants) by means of GC (Figure 3.27). Further HC1/HF treatment of the hydrolysis residue, which is composed of mineral fillers, CB and nonhydrolysable polymers (e.g. impact modifiers) permits determination of total IM and CB contents CB is measured quantitatively by means of TGA [157]. Acid hydrolysis of flame retarded polyamides allows to determine the adipic acid content (indicative of PA6.6) by means of HPLC, HCN content (indicative of melamine cyanurate) and fatty acid (indicative of a stearate) by means of GC [640]. Determination of ethylene oxide-based antistatic agents... 

On-line SFE-GC-MS was used for the analysis of organic extractables from human hair [312]. Van Lieshout et al. [313] described GC-MS analysis of an SFE extract of an (ABS) impact-modified PC/PBT blend identifying Ionol CP, Dressinate, cyclic PBT trimer, Irganox 1076 and Irganox PS 800. TD-GC-MS was used in the development of flame retardants, and for the analysis of fire debris [314]. The application of laser desorption fast GC-MS analysis was employed in the analysis of DOP on a stainless-steel surface [221]. 

---