Stabilisation processes

Dilution or simple mixing with a stable compound is sufficient to stabilise an unstable substance. In the case of a simple mixture with a neutral substance, this stabilisation process is called desensitisation . Thus hardeners such as benzoyl peroxide are nomially in the form of suspensions in heavy esters or oils. This peroxide is mixed with 30% of water by weight. Dynamite is nitroglycerine stabilised with the help of a neutral material. In all these cases, heat that is produced by the potential beginning of decomposition is absorbed by the inert substance. 

A high level of stabilisation is achieved at low concentrations. This is because of a cyclic process whereby the HALS are regenerated rather than consumed during the stabilisation process. This also promotes long-term protection. 

The role that acrylic processing aids play in compound processability, end product properties and manufacturing efficiency has been reviewed (79). The functions of acrylic process aids, with very high molecular weight, have also been discussed from a rheological point of view (290). Co-stabilising process aids have also been developed (335). 

The study of PVC stabilisation by stannic compounds in the presence of HC1 scavengers shows that the essential stabilisation process is nucleophilic substitution of the allylic chlorine by the thioglycolate or mercaptopropionate groups. It is claimed that their capability to form complexes with HC1 and transport this degradation catalyst to HC1 scavengers are essential for the marked synergism observed between these two types of stabilisers. 14 refs. 

The timing of the compaction process is still a matter of debate. It should be delayed sufficiently to ensure that all of the quicklime is fully hydrated, to avoid expansion. If it is delayed for too long, however, the stabilisation process will have progressed to a significant degree and the final strength of the lime treated layer will be reduced. The need for a maturing period is discussed in section 26.3.5. 

A new book has appeared on the principles of polymer stabilisation processes while there have been other reviews on weathering and bio and photodegrad-able polymers. Articles of topical interest include humidity effects during weathering and the role of sulfur and nitrogen oxides. ... 

Optimisation of the parameters that enhance waste degradation (and stabilisation) processes, will result in enhanced microbial activity within the waste, and more active methanogenesis. Under these conditions, the co-disposal of industrial and hazardous waste will be more effectively achieved. 

In the case of the additive stabilisation process, the percentage of the hydraulic binder to be added as well as the amount of water should always be determined in the laboratory by executing CBR, M, (resilient modulus) or unconfined compressive strength tests, whichever is appropriate. 

Incorporation of additives such as stabilisers, processing aids and so on. 

In most cases, polymers need stabilisation or additives in order to meet the requirements of the intended application. Thus, antioxidants, UV-stabilisers, processing aids, etc. may be added after the actual reaction but before forming the pellets. 

Type and efficiency of sludge stabilisation process (e.g. anaerobic digestion). Sludge age. 

Formed during processing as a result of the Irgafos 168 performing its role as a melt stabiliser this is a benign material taking no further part in the stabilisation process. 

As well as the direct production of polymers, vegetable oil derivatives have other uses in the polymer industry, for example as additives. Materials made from vegetable oil have many uses and are used to produce anti-static, slip, and plasticising agents, stabilisers, processing aids and as flame retardants (see Section 2.4.). They can also be incorporated into the manufacture of polyamides, polyesters and polyurethanes. 

At Canons Park a 2-3Km of innovative embankment stabilisation process using lime columns was introduced for the first time in the UK. This was satisfactorily competed as an Infrastructure System Project and ongoing track and embankment monitoring remains in place giving a cost effective and significantly reduced method of earthworks stabilisation and improved track performance, both Items working as an Infrastructure System In support of the Business. 

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