Plastic Mixtures

The pyrolysis produets obtained from a variety of mixed plasties eontaining PVC are investigated. While hydroehlorie aeid is the major chlorinated product produced by PVC pyrolysis, other chlorinated hydroearbons are produced. However, the composition and yield of these compounds are very much dependent upon the other polymers present in the plastic mixture. In the ease of a polymeric waste stream containing inorganic fillers, sueh as ealcium carbonate, the HCl produced by the PVC ean be neutralised in situ, leading to the produetion of inorganic chlorides, alleviating many of the concerns associated with HCl formation. 9 refs. 

Macromolecular Symposia Vol.135, Dec.1998, p.35-41 STEPWISE PYROLYSIS FOR RECYCLING OF PLASTIC MIXTURES... 

Bordeaux, 22nd-23rd Sept. 1993, p.59-64. 627-8(13) LOW TEMPERATURE PYROLYSIS FOR CHEMICAL SEPARATION OF PLASTIC MIXTURES... 

H. Thoma, G. Hauschulz, E. Knorr and O. Hutzinger, "Polybrominated Dibenzofurans (PBDF) and Dibenzodioxins (PBDD) from the Pyrolysis of Neat Brominated Diphenylethers, Biphenyls and Plastic Mixtures of these Compounds,"Chemosphere, JJi, 277(1987). 

The investigation into the sabotage of Pan Am Flight 103, which left 269 dead, indicated that the explosive used was Semtex H, a plasticized mixture of hexahydro-l,3,5-trinitro-s-triazine and pentaerythritol tetranitrate, and that the amount used was half the quantity that the fledgling technique of Thermal Neutron Analysis (TNA) was designed to detect. Although the placement of the explosive device was fortuitous (from the terrorists point of view) and the suitcase had not been screened by TNA, this event killed the TNA prototype program. 

Bis(2,2-dinitropropyl)acetal/formal (BDNP A/F) Liquid plasticizer mixture (50% BDNPA and 50% BDNPF) used in PBX compositions... 

Chromatography has been carried out ascendingly with a mixture of pyridine, ammonia, isopropyl alcohol, and water as eluent. At the starting point, 0.001 ml. of the plasticizer mixture was applied, and the chromatography was completed within eight hours. The paper subsequently was dried in hot air at 85° C. and then, at room temperature, was gradually treated with Universal indicator solution (British Drug House). 

The same effect is borne out by our experiments. The Tf s of solvent-cast nlms were higher than those clot era lined on pressed films made from the same polymer plasticizer mixtures. 

Under selected conditions, polymer plasticizers remain at the starting point. Although variation of the mobile and stationary phases and detection reactions allows selectivity of TLC to be increased, methods such as gas chromatography must be used for more complex plasticizer mixtures. 

The gas-chromatographic separation of plasticizers can be effected directly or after conversion to low boiling point compounds. This is achieved by a transesterification reaction with methanol or diazomethane. After separation of the plasticizers mixtures with liquid chromatography, identification by spectroscopic methods is possible. 

Diepoxyethylbenzene was first prepared by Everett and Kon (3) as a liquid which evidently was not pure because analysis showed a difference of 4% in the carbon content. Our product was a white crystalline mass with melting point 79°C. and boiling point 95°C. at 0.06 mm. Catalytic hydrogenation gave the theoretical absorption. The stabilizing effect in PVC mixtures was about 30% of dibutyltin laurate—i.e., 3.3 times more of the stabilizer is necessary to obtain the same discoloration as dibutyltin laurate in a plasticized mixture of PVC with 30% dioctylph-thalate at 200°C. for 20 minutes. 1,3,5-Triacetylbenzene was prepared by the two methods mentioned above. 

Extensive use is made in embedding in the plastic various ornamental or utilitarian objects. The process provides means to easily incorporate different product requirements such as coloring and texturing. The plastic mixture may contain pigments, fillers, plasticizer, and other chemical additives. They can include reinforcements providing aesthetic to increasing strength (Chapter 15). 

Properties More sensitive than the modern Permissible Explosives. The Perchlorate Explosives are less sensitive to detonation and therefore safer than the Chlorate Explosives. The plastic mixtures containing nitroglycerine are somewhat less sensitive to shock and friction, in spite of the nitroglycerine present, than the drier explosives with no nitroglycerine. 

Thoma H, Hauschulz G, Knorr E, Hutzinger O (1987), Chemosphere 16 277-285. Polybromi-nated dibenzofurans (PBDF) and dibenzo-p-dioxins (PBDD) from the pyrolysis of neat bromi-nated diphenylethers, biphenyls and plastic mixtures of these compounds"... 

Process heat requirements tend to be lower if the feed is stepwise heated, as in certain multistep or selective decomposition schemes of plastics mixtures, or in case the... 

E. A. Williams, P. T. Williams, The pyrolysis of individual plastics and a plastic mixture in a fixed bed reactor. Journal of Chemical Technology and Biotechnology, 70 (1), 9-20, 1997. 

Likewise, Tang et al. [95] have investigated the catalytic cracking of mixtures of several polyolefins and PVC (PP/PVC, PE/PVC, PS/PVC) at 360-380°C over a novel Al-Zn composite. These authors observed that the composite accelerated the degradation of the plastic mixtures and retained the chlorine resulting from PVC degradation. 

An alternative process based on two sequential catalytic cracking stages aimed at obtaining gasoline and diesel from waste plastics or heavy oil/waste plastics mixtures is shown in Figure 3.16 [99]. The catalyst employed in the first step is made up of powder alumina, waterglass and HZSM-5 zeolite and is mixed up directly with the waste plastics in a screw reactor preferably at 600-700°C. The second catalytic step consists in a fixed... 

In the first step, the plastics mixture (either a model one made up of 50% HDPE, 30% PET and 20% PS or an actual mixture formed primarily of HDPE and PP) was catalytically degraded at 440°C under 2.8 MPa of H2 over different catalysts (HZSM-5 zeolite and... 

M. Luo and C. W. Curtis, Two stage coprocessing of coal with model and commingled waste plastics mixtures. Fuel Process. Technol, 59, 163 (1999). 

A batch-type reactor equipped with a screw feeder and mixer is offered by US patent [49]. A special grate is mounted inside the reactor, above the cracked melted waste plastics mixture. Scraped waste plastics which are submitted to the cracking reactor melt at the grate and fall down to the reaction mixture. As in the case of previous patent description, in the course of cracking process a mixer of a special construction scrapes coke form the reactor walls and then coke is removed from the specially shaped reactor bottom by a screw transporter. The process temperature attains level of 450° C. 

Development of a Process for the Continuous Conversion of Waste Plastics Mixtures to Fuel... 

Terephthalic acid is a useful source material of PET, as well as benzoic acid and benzoates. However, in order to recycle the terephthalic acid, produced further purification is required, because other organic compounds are also produced as impurities in the degradation process of waste plastic mixtures, e.g. PE and PET mixtures described in Section 2.3. 

CONTINUOUS DEGRADATION OF WASTE PLASTICS MIXTURES FOR THE RECOVERY OF HEAVY OIL... 

---