Plastics

Durable agricultural films with chemical resistance - microencapsulated plastic additives

The plastic additives for agricultural films developed in the project - allowing stable encapsulation with melamine resins - do not satisfactorily withstand the high thermal and mechanical loads of the (industrial) compounding process. Nevertheless, the findings on compounding of microcapsules with varying core materials and the requirements identified for industrial use are extremely valuable for further research.

 

Summary

Greenhouse films used in agriculture to protect cultivated crops have a relatively short service life of just two years. To extend this to three or more years, micro or nano-scale particles could be used as functional additives in polymer materials. Microencapsulation of the active components allows stabilisation and controlled release of the substances. Depending on the application, however, the wall materials and/or encapsulation technologies must be adapted, but little information and experience is available for compounding in polymer melts.

Thus, the aim of the project is to develop microencapsulated plastic additives and methods for efficient production of them. 

Results:

  • The selected benzophenone and benzotriazole compounds can be microencapslated from melt and as a solid.
  • The microencapsulated additives are effective at forming compounds and master batches and films could be produced with no problems.
  • The measuring and analysis methods devised support determination of capsule effectiveness and thermal stability of microencapsulated additives, along with quality control on the compounded microcapsules. This allows appropriate capsule systems to be preselected.
  • The stability of the microencapsulated additives was significantly improved by modifying the capsule technology and the capsule wall material. For flat films produced under optimised compounding conditions with modified microcapsules, a stability improvement of up to 75% was identified.
  • The weathering tests did not reveal any improvement in stability when using the optimised microcapsules. It was therefore assumed that despite the improvements achieved in laboratory and technical centre tests, thermally initiated permeation of the additives through the capsule wall is still likely to occur.
  • The findings and experience acquired during the project, particularly in relation to compounding of microcapsules with varying core materials and in terms of the requirements for microcapsules for industrial use, provide an important basis for further research and development work in the field of microencapsulation.

Promotion

Promoting institutions

Federal Ministry of Education and Research (BMBF)

Promotional program

Chemie / Kunststoffe

More Project Informations

Project title:  Verbundprojekt: Entwicklung eines modularen Masterbatch-Systems sowie einer neuartigen Folienarchitektur zur Herstellung langlebiger Agrarfolien mit verbesserter Resistenz gegenüber Agrarchemikalien - Teilvorhaben 2

Project number:  01RC0202

Project period:  2002 - 2006

Project region:  Germany (Brandenburg)

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Source: German National Library of Science and Technology Hannover (TIB)