Accessibility navigation


Investigating water-soluble polymers as rainfastness adjuvants for agrochemicals

Symonds, B. L. (2017) Investigating water-soluble polymers as rainfastness adjuvants for agrochemicals. PhD thesis, University of Reading

[img]
Preview
Text - Thesis
· Please see our End User Agreement before downloading.

3MB
[img] Text - Thesis Deposit Form
· Restricted to Repository staff only

103kB

It is advisable to refer to the publisher's version if you intend to cite from this work. See Guidance on citing.

Abstract/Summary

Rainfastness is the ability of agrochemical deposits to resist wash-off by rain and other related environmental phenomena. This work reports studies of the rainfastness of selected water-soluble polymers, including poly(vinyl alcohol) (PVA) and chitosan, on Vicia faba leaf surfaces. This was achieved using a novel method involving fluorescent microscopy combined with image analysis. The retention of polymer deposits was analysed via lab-scale washing to simulate rain. PVA over a threshold molecular weight and chitosan were shown to be excellent rainfastness aids. The washing method was scaled up with the use of a raintower and it was shown that the lab-scale washing method was representative of low-to-medium intensity rain (10 mm/h). Physical characterisation indicated that rainfastness correlated with polymer film dissolution, swelling and crystalline properties. It was established that the rainfastness of PVA scaled with increasing molecular weight and crystallinity. Chitosan proved the most effective of the polymers analysed and even samples of moderate molecular weight were able to resist the highest intensity simulated rain. Those polymers which exhibited rainfastness were only soluble in water with a stimulus, such as heating for PVA or decreased pH for chitosan. The microscopy analysis was expanded to assess the rainfastening effect of these polymers on a model agrochemical. This was achieved by following the retention of azoxystrobin – a fluorescently active fungicide. Those polymers which showed retention alone also improved the retention of azoxystrobin. A spot and wash‘ method using mass spectrometry to quantify rainfastness performed alongside fluorescent microscopy analysis further validated the findings.

Item Type:Thesis (PhD)
Thesis Supervisor:Khutoryanskiy, V., Thomson, N. and Lindsay, C.
Thesis/Report Department:School of Chemistry, Food and Pharmacy
Identification Number/DOI:
Divisions:Faculty of Life Sciences > School of Chemistry, Food and Pharmacy > School of Pharmacy
ID Code:77825
Date on Title Page:2016

Downloads

Downloads per month over past year

University Staff: Request a correction | Centaur Editors: Update this record

Page navigation