Soil burial test composite

SEM micrographs of biodegradable polymer green composite, tested by the soil burial test. 

The loss of TS observed by Shubhra et al. is shown in Figure 9.8. It was found that TS values of the composites decreased slowly. For silk fibre/PP composites the TS value was 54.7 MPa whereas after 24 weeks of soil burial test it was 49.1 MPa. So, after 24 weeks of soil burial, silk fibre reinforced PP composite lost 10.2% TS, whereas silk-reinforced PP and NR blend (50 50) composite lost 24.3% TS. For silk-reinforced PP and NR blend (50 50) composites the TS value was 39.9 MPa whereas after 24 weeks of soil burial test it was 30.2 MPa. The author mentioned that this 14.1% higher loss of TS is due to incorporation of NR in the PP matrix. The author found that if NR is low (25% instead of 50%), the composite loses less TS value after 24 weeks of degradation test (from 42.4 MPa to 34.3 MPa, which is 19.1%). 

The loss of BS observed by Shubhra et al. is shown in Figure 9.9. It was found that BS values of the composites decreased more rapidly than TS values. For silk fibre/PP composites the BS value was 58.3 MPa whereas after 24 weeks of soil burial test it was 50.7 MPa. So, after 24 weeks of soil burial, silk fibre reinforced PP composite lost 13% BS whereas silk-reinforced PP and NR blend... 

Figure 9.8 Loss of tensile strength of rubber composites during soil burial test.

Figure 11.1 SEM images of the samples before and after the soil burial test, (a) TPU/ NR blend, (b) TPU/NR chitin reinforced composite.

Routray M, Rout SN, Mohanty GC, Nayak PL (2013) Preparation and characterization of soy protein isolate films processed by compression and casting. J Chem Pharm Res 5(11) 752-761 Sareena C, Sreejith MP, Ramesan MT, Puiushothaman E (2014) Biodegradation behaviour of natural rubber composites reinfOTced with natural resource fillers—monitoring by soil burial test J Reinf Plast Compos 33(5) 412—429... 

Three different films obtained by a hot pressing procedure of powder mixtures containing plasticized PVA, PVAc with and without bactmal PHB were submitted to the biological degradation of soil microorganisms in a respirometric test aimed at simulating soil burial conditions. The compositions of the blend films are summarized in Table 1. 

Although all these complicating factors cannot be reproduced in small-scale tests, it will be of value to summarise the main knowledge that has been gained from long-period burial trials conducted in the United States and in Great Britain . The subject will be considered under two heads effect of metal composition and effect of the soil. 

Binary munitions are those in which the chemical substances are held in separate containers and react when mixed or combined. This may happen during firing, launching, or by other initiation methods. The product is a chemical agent or material agent. Binary components must be tested for individually because in a burial situation they may not be combined. Care must be taken not to mix chemical agents found at post-World War II sites (i.e., compositing soil samples). 

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