The development of techniques to formulate and study gel systems is something which is of great interest to R&B Research and the systems can take several forms including:
- Oil external microemulsion gels where the structural elements can be modified using a simple water enrichment process and where the carrier oil can impart functionality to the system.
- Conventional water based gels using a range of natural occurring structure forming materials.These systems can be used for a variety of applications including simple ant bait stations to more sophisticated means of controlling the deposition properties of herbicides and fungicides onto plant surfaces to improve selectivity whilst reducing environmental impact.
- More sophisticated gel systems where the addition of gel components is more than just as a means of increasing viscosity; this can include the use of structure formation to lock up water for instance in a rodent treatment product.
A detailed understanding of rheology under a wide range of conditions is essential in the study of these types of system and at R&B Research we use Cone & Plate geometry to study these formulations. In addition the development of analytical techniques and the use of phytotoxicity studies on model plant species helps us to understand how the gel is behaving under a wide range of conditions and processes.
This area of our work can be broken down into three distinct fields of study:
- Development of concentrated liquid feed systems containing high concentrations of primary nutrients (N-P-K) coupled with a broad selection of micro-nutrients. This work is primarily targeted at the hydroponics and home & garden market sectors.
- Development of novel and innovative fully-solubilised systems where the inclusion of specific solubilising or complexing agents allow the formation of highly concentrated solutions of materials such as Caffeine, Vanillin and other natural extracts thereby increasing significantly their usefulness as commercial alternatives to conventional synthetic chemistries.
- The utilisation of specially designed surfactant systems for use as tank-mix adjuvants to enhance the performance of existing formulations. The types of components used may improve rain-fastness, UV stability, deposition characteristics, uptake/ translocation and surface wetting.
A wide range of techniques have been developed at R&B Research and these include:
- Measurement of dynamic contact angle on a range of surface types.
- Measurement of interfacial and surface tensions
- Analytical methods to determine residuality of deposits when subject to artificial rain or high levels of UV radiation
- Microscopy to examine deposition characteristics
This is a relatively new field of research within our labs and currently we are looking at these formulation types as a means to:
- Reduce or modify the evaporative loss of a herbicide following low volume application to soil.
- Improve the stability of a concentrated fungicide system in which the active ingredient is inherently unstable and is not suitable for formulation in emulsion systems
- Control the rate of release of an insecticide when used in a combination of an encapsulated active ingredient in an external O/W microemulsion system containing other insecticides which are designed to give rapid knock-down.
- Develop multi-active formulations as a means of resistance control.
A number of techniques are being developed by our scientists both in terms of formation and stabilisation of the encapsulated particles and in the techniques used to study specific performance characteristics such as particle size, friability, rate of release etc.
This field of work is one in which our team of scientists specialise having gained an international reputation over a long period of time. We continue to develop and improve the technology in order to further enhance performance whilst bringing down costs. The range of active ingredients and applications studied at R&B Research is very extensive but our work would include:
- Development of multi-active (carbamate + pyrethroid + nicotinoid) insecticide microemulsion for the control of resistant bed bugs where we were able to significantly improve the speed of knock-down , reduce the LC50 values and improve residuality in a highly stable formulation.
- Development of a highly concentrated organophosphate formulation where the use of a novel and innovative carrier/ surfactant system allowed us to achieve loadings much above expectations. When compared to conventional formulations the efficacy in the field was circa 2-3 times better.
- Development of a natural plant extract formulation where we were able to increase the efficacy levels to the point where it was equivalent to conventional synthetic triazole fungicides with far superior dilution stability and rain-fastness.
- Development of techniques to examine the effectiveness of microemulsions to control the movement and positioning of active ingredients on to soil when applied through surface treatment.
- Development and testing of a very wide range of products for application in the agrochemical, professional pest control, timber treatment and home & garden sectors where a variety of approaches are needed to meet the diverse challenges of the various sectors.
In developing microemulsion formulations we would use an array of different techniques some of which we have developed and adapted in our own laboratories but these would include:
- Measurement of interfacial tension as part of the surfactant selection process
- The use of detailed phase mapping to elucidate the structural changes following water enrichment
- The use of detailed conductivity profiling to predict stability of microemulsions
- Particle size analysis and turbidity to study the stability of dilutions or of o/w RTU systems
- The use of drop shape analysis to determine dynamic contact angle and to study the wetting and spreading properties of dilutions and the effect of selective additives
- Analytical techniques linked to centrifugation to determine phase stability of microemulsions
- In house phytotoxicity studies to aid in selection of safer surfactant systems
Suspensions & Dispersions
At R&B Research we have carried out a range of studies aimed at improving or developing systems in which a variety of solid active ingredients have been formulated as stable dispersions or suspension concentrates. The nature of the active ingredients studied have varied considerably and include:
- Biological systems where better dispersion and suspension of a bacterial culture was required for optimum biological efficacy and product stability.
- Systems in which a blend of natural clays were suspended and dispersed in a ‘soup’ of micronutrients. In these systems the clay acts both as a source of nutrient and as a means of preventing crystal formation and sedimentation of other inorganic nutrients.
- Feed systems based on very high loadings of water insoluble inorganic compounds where the suspension properties of the concentrate and dispersion properties of the dilution are paramount for good performance in the field. These systems need to remain effective when tank mixed with a variety of other materials such as fungicides or herbicides and this requires careful selection and manipulation of the surfactant system to avoid potential incompatibility issues.
A number of techniques are employed by our team of scientists in the development stages of these types of system and these would include:
- Sophisticated rheological studies to optimise flow properties and suspension of solid particles.
- Use of Drop Shape Analysis techniques to study and elucidate effectiveness of surfactants used as wetting agents or dispersants
- Standard suspensibility tests in ASTM sedimentation tubes linked with centrifugation techniques and microscopy.
- Analytical techniques to look at phase stability of the systems.