**5. Conclusions**

In **Figure 12**, we can see the response of viscous parameter *n*1, which allows the calculation of the strain rate for creep tests; this exercise was carried out, varying the volume of natural fibers fique biocomposite, corroborating the possibility of deepening the study of the effect of

**Figure 13** shows the setting of the four-parameter model, two biocomposites, with different volumes of natural fiber reinforcement sisal. It is possible to corroborate and validate the

**Figure 13.** Setting the four -parameter model to LDPE-Al-Fique 10 and 30% incorporation biocomposites of fibers.

using the weighted sum of squares (weighted sum of squares, WSS), using Eq. (12):

**Parameter 10% 30%** E1 (Pa) 1.10E + 09 1.50E + 09 E2 (Pa) 4.79E + 09 1.53E + 10 E3 (Pa) 7.91E + 09 8.39E + 07 N1 (Pa.s) 1.49E + 13 3.12E + 13 N2 (Pa.s) 6.48E + 11 9.32E + 11 N3 (Pa.s) 7.83E + 13 3.33E + 15 WSS 9.23E-08 6.43E−08

10 and 30% incorporation biocomposites of fibers.

**Table 7** shows the adjustment of the different parameters for a model of six parameters, including error, which is the estimate of least squares adjustment parameters can be obtained

**Table 7.** Parameters of creep tests obtained by adjustment to a model of six parameter biocomposites LDPE-Al-Fique

() ()

 eÙ

*ii i*

é ù = - ê ú

1

=

*i WSS w t t* e

*n*

2

ë û å (12)

reinforcements or fillers to biocomposites.

324 Composites from Renewable and Sustainable Materials

model.

Natural fibers as reinforcement of nonbiodegradable and biodegradable polymers have been used for decades for the development of various products, especially in the automotive, construction, and packaging industry. The importance of studying the viscoelastic behavior of biocomposites lies in understanding the impact of natural fibers or fillers on any scale, in the matrices that you want to use for different applications. Now, it is known that the structural rigor for automotive, construction, and/or packaging parts lies mainly in the relationship of the shape of the products with the stresses to which these materials are subjected, temperature changes, environmental and even other physicochemical factors that could alter the performance of the biocomposite in time. The articulation of theoretical models and experimental results using the technique of dynamic mechanical analysis (DMA) to predict the behavior over time, and the effect of filler or reinforcement, nanoreinforcements, micromechanics, surface treatments to the fibers, or modifications to polymer matrices facilitate a better understanding of its operation and its use at an industrial level for various applications. In South America, the natural fibers have recently become an attractive reinforcement or filler for researchers, engineers, and scientists as an alternative to develop biocomposites. Because of its low cost, sometimes good mechanical properties and good specific resistance generate a high environmental impact and additionally, it is biodegradable. It has been found that the use of natural fibers such as fique of South American Andean region can be used as reinforcement in composite materials and generate a lot of possibilities for industrial applications. It was found that the addition of fibers in different polymer matrices leads to produce new natural compounds with good physical properties for use in different sectors. The study revealed that biocomposites inherited effects relaxations attributed to transitions suffered by the polymer matrices used, whereby the relationship of fibermatrix-filled showed evidence that the biocomposites always have a positive effect creep (creep), however, and while being exposed to constant loads over time and while working above the glass transition temperature, the biocomposite will behave predominantly as a super-cold fluid, and not likely as an elastic solid.
