**5. Biopolymers and biodegradable textiles industry**

The textile industry has played a important role in the exchanging of goods and impacted by novel techniques through the development of more environmentally friendly processes [64–67]. Many biodegradable fibers may be natural, regenerated or synthetic such as Ingeo (Natureworks), LLC produced from corn, a biodegradable thermoplastic polyatide (PLA); Lenpur produced from wood pulp of harvested white pine tree clippings; and Modal and Tencel/Lyocell produced by Lenzing from wood pulp of beech and eucalyptus trees, and biodegradable aliphatic/aromatic multi-block co-polyesters. The largest application of alginates in textiles can be found in textile printing, the spinning and weaving of temporary fibers from calcium alginate [15]. Bio-based fibers like X-Static, Meryl Skinlife, Diolen Care, Trevira Bioactive are enriched with innovative antimicrobial products such as technical products, working uniforms, sportswear [68].

#### **5.1 Fibers industry and biodegradable polymers**

The melt spinning processing technologies with availability of biodegradable materials along have aided in qualitative and quantitative improvements [69]. The fibers reinforcing improve the relationship between the process parameters and the material properties [70]. Many natural fibers added to biopolymers as reinforcements (flax, cellulose acetate, bamboo, pineapple, ramie, kenaf, henequen, jute, sisal, and hemp); improving the strength without affecting the biodegradability [71]. Fibers of the poly(β-hydroxybutyrate) were produced via multistage melt-extrusion as well as gel-spinning [72]. The dry-jet wet spinning method was used to extrude the cellulose/ NH3/NH4SCN solution [15]. By "dry-jet wet spinning" and using a cellulose/hydrolyzed starch-grafted-polyacrylonitrile solution, the mechanical properties of Lyocell fibers were improved [73]. An extruded Lyocell fibers were reported have potential uses in filters, geo-textiles, surgical gauze [74]. Cellulose fibers are used for the design of intelligent, bioactive, and biocompatible composites [75]. Preparing sol–gel derived biodegradable SiO2 gel fibers [76] for drug release consists of three steps: an initial burst, followed by a diffusion-controlled release behavior, and finally a step with a slower release rate. By incorporating responsive hydrogels in textiles, the surface energy switches between hydrophilic/hydrophobic, with the results listed in **Table 3** [77].

There is good compatibility between the chitosan obtained from shrimp shells and starch-based polymers when forming a chitosan/starch fiber. Some researchers have made fiber from starch and biodegradable glycerine-based polymers with/ without PLA and glucitol, while others extrude high strength PLLA fibers. The type LA 0200 K of PLA is processed at a high speed spinning (draw ratio = 6)in a spin drawing [78]. A fiber from soya bean protein is crafted by forcing a globular protein to become a fiber forming protein; the fiber has to be cross-linked if fibrous products are to be obtained [79]. Fibrous materials are segregated into two basic groups, the first can be placed on the surface of materials (i.e., surgical covers, gauzes, diapers and tampons), and the second can be placed inside an organic tissue (i.e., surgical threads, tendons and ligament implants, meshes, stents, and vascular grafts).


**Table 3.**

*Monomers, origin and fiber formation of smart biopolymers [77].*

#### **5.2 Fabric industry and biodegradable polymers**

Weaving, knitting, nonwoven web forming (carding, spun-bond and wet-laid) and nonwoven-bonding (stitch-bonding, needling, calendaring and hot air bonding) are fabric forming technologies. Biodegradable non-woven webs and disposable articles contain fibers such as cotton, hemp, milkweed floss, flax fiber, wool, silk, chitin and chicken feathers [80]. There are many examples in biodegradable nonwoven such as biodegradable cotton-based nonwovens (cotton/cellulose, or cotton/ biodegradable co-polyester) and (PTAT co-polyester and PLA). Cotton/(co-polyester/PP) nonwovens along with absorbency and flexural rigidity have suitable mechanical properties and they are better than that of cotton/co-polyester nonwovens [81–83].

Sanitary and medical textiles, geotextiles, filtration media, within the automotive industry, PLA based hair caps, Bionolle 3001 nonwovens, Landlok biodegradable erosion control coconut fibers mats, Kenaf fiber nonwovens, refuse bags, drain filters made from fine denier PLA nonwovens, and biodegradable filter materials are used for both air and liquids. A biodegradable thermoplastic polymer and a plasticizer could be used to produce a starch matrix of the finely attenuated fibers which could have applications as environmentally degradable nonwoven webs and articles [84].

Researchers have produced biodegradable cotton-based, nonwovens by using blends of cotton, flax and biodegradable thermoplastic fibers that act as binders [85]; Biodegradability was monitored, with 40% of the initial weight lost after 8 weeks composting [86]. To reduce the cost, researchers have made a pure nonwoven material from co-polyester by a direct melt-blowing process [87]. Woven tubes (3 to 6.5) mm are developed using Polyglactin 910 biodegradable yarn on a narrow width loom [88].

Biodegradable poly (L-lactide-co-caprolactone) fabrics of nano/micro- structured can be made Using CH2Cl2 as a solvent in electro-spinning. The electro-spun elastomeric nano-fiber fabric is used as a functional scaffold in tissue engineering (i.e., cardiovascular, muscular) [89]. The Belgian Textile Research Centre's projects include: Noterefiga for

*Characterization, Modeling and the Production Processes of Biopolymers in the Textiles Industry DOI: http://dx.doi.org/10.5772/intechopen.96864*

bio-based comfort textiles, Bioagrotex for agro-textiles (agriculture, horticulture, gardening and construction), Green-Nano-Mesh for medical areas, Dura cover for woven PLA taped ground covers, Hortaflex and Weed Control for PLA based nonwovens, and the BiobasedFilbio project for knitted PLA insect screens for climate control.

There are various commercialized fabrics made from naturally derived biopolymers such as those found in the Ethical Fashion Forum in London: POLY Acid Ingeo bio fibers; QMilchfibers, Lenzing's Modal fiber, Micro Modal fiber, Lyocell fiber, POLARTEC polyester, unique corn-based PLA fleece; and Cork shell made from cork to form high quality textiles for lightweight spring and summer jackets. Biopolymers based in intelligent and/or stimuli responsive polymeric systems have been developed and reported by researchers for the functional finishing of textiles [90]. Scientists proposed changes of the polymer backbone in a reversible formation of PLA-dye complexes [91]. Sorona is used in the coat fabric for jackets, trench coats and outerwear with its 37% renewably sourced plant-based components; they lose their wrinkles with one quick snapping motion. Bio-based fabrics made of wool and "BIOPHYL" or "TENCEL". Some commercial products are made from spider silk [92] and could be used in the bullet-proof vests industry [15].

#### **5.3 Fiber and fabric coatings and biodegradable polymers**

Modification techniques of the biopolymer's surface includes coating, oxidation by low-temperature plasma, and surfactant addition blending with various derivatives [93]. Cyclodextrins or linear carbohydrate biopolymers were attached to the textile to allow frequent use and washing [94]. Regenerated cellulose fibers were treated by plasma activation using a chitosan solution [95]. Cellulose was coated by chitosan nano-particles to reduce the cost and non-toxic methodology [75]. While studying their development as well as characterization, both the organic cotton based bandages and cotton were coated separately on the gauze structure using chitosansodium alginate polymer, calcium-sodium alginate polymer and subsequent mixtures of the two, thereby improving its antibacterial and wound healing properties [96]. For dyeing and printing, the dextrin derivative surfactant improves the whiteness and wetting properties of cotton fabrics [97]. The chemical surface treatments of jute fabrics involve bleaching, dewaxing, cyanoethylation, alkali treatment and vinyl grafting are used as reinforcing components in biodegradable matrix composites, which are environmentally friendly materials [98]. A Knitted Dacron graft made of polyethylene oxidepolylactic acid were coated with a polymeric biodegradable sealant [99]. Layer-by-layer electrostatic deposition is used to coat the material by adding dextran sulphate and chitosan to a soybean based polymer [100]. The functional finishing of the micro- and nano-sized hydrogels improve response times [101].

Nano-composites and nano-structured coatings improve mechanical strength and flexibility, temperature and moisture stability, as well as durability. "Metal Rubber"(Nano Sonic Inc.) combines the rubber and metal properties, and it is used in artificial muscles, electrically charged aircraft wings, and protective biopolymer clothing [102]. Hydrogel-based biopolymers are used for the functional finishing of textiles by surface modifying systems [103].

#### **6. Case study: modeling of biopolymers' melt spinning process**

All the production process parameters must be controlled to ensure the quality and then the significant main factors must be analyzed [104]. Commercially, it is a challenge to develop a new competitive product [105]. Some research is based on statistical analysis, mathematical simulation and modeling of the processes of fiber formation, and examples of their post-processes have been reported in literature [106–116]. The practical software-based approach has improved the confidence benefits of experimental design and simulation [117]. **Figure 3** shows a flow chart for the methodologies used for obtaining the program, starting from the data and statistical modeling methods and SED. Online quality control tools were utilized for prediction, measurement, correction as well as adjustment and feedback [118].

The aliphatic aromatic co-polyester fibers extrusion process was investigated in this work, and statistically modeled [119]. A linear biodegradable oil-based polymer (LAAC-flexibility component of Solanyl) and branched aliphatic-aromatic copolyester (BAAC-Ecoflex F BX 7011) were used to study the effects of the extrusion process and the properties of fibers. The study describes the melt spinning of aromatic-aliphatic co-polyester depending on the extrusion thermal profile effect on asspun fiber properties. The molten material flowed easily when the viscosity decreased and smoother extrudates were obtained at shear rates greater than 4.5 s-1 [120].

## **6.1 Factorial experimental design for melt spinning of biodegradable fibers**

Factorial experimental design provides data about the optimization of the average response values in regards to the factor levels [121]. The STATGRAPHICS program is used to design the experiment random order matrix and to simulate the main data in one block experiments.

The studied factors for the fiber extrusion process include: speed of spin finish, quenching air speed, metering pump speed, and winding speed, as well as, meltspinning or extrusion temperature. The analyzed levels of each parameter were listed in **Table 4**; the thirty-two trials matrix for the five control factors was applied for as-spun fibers analysis. **Figure 4** shows an SEM photomicrograph of the crosssection and surface of the fibers; fibers had an acceptable uniform surface and possessed a uniform circular cross section.

In this case study [122–124], several statistical tools were utilized for statistical analysis including the surface plot, normal probability plot, the main effect plot, pareto chart, interaction plot, as well as analysis of variance (ANOVA). Implementation of forecasting statistical methods plays a major role in creating a planning program and

**Figure 3.**

*The flow chart of the statistical method.*


**Table 4.**

*Factors and the selected levels for the spinning experiments of as-spun fibers.*

### *Characterization, Modeling and the Production Processes of Biopolymers in the Textiles Industry DOI: http://dx.doi.org/10.5772/intechopen.96864*

a plan for the production process regression. A detailed experimental arrangement of the calculated results of spin draw ratio, birefringence, drawability, die head pressure, crystallographic order as full-width half-maximum (FWHM), filament temperature averages, count, tensile properties, diameter, and thermal shrinkage was completed. According to the drawability characterization, biodegradable fibers (i.e., as-spun) should consist of a drawn construction and be conducive to orient along the fiber axis of the chain [125]. There is a clear relationship between the draw down ratio and the orientation of the fibers and having a significant effect on the drawability. In other words, the overall orientation of fibers was increased and the draw ratio decreased as the spin draw ratio increased. Temperature significantly influenced the spin (down) draw ratio and fiber drawability that affects the flow rate and tension value. To study the effects of the factors as well as their statistical significance an ANOVA study was conducted. A factor was considered to have a significant effect if the F ratio (an ANOVA statistic) was shown to be more than the statistical value (F /4.49/at the appropriate level α =0.05) or had P-value smaller than 0.05. The ANOVA results from the experiments are presented in **Table 5**.

**Figure 4.** *The surface and cross section of the biodegradable fibers [119].*


**Table 5.** *ANOVA results of factor effects on the drawability.*

The significance of factors were PWS > PMPS> PT in the drawability analysis, while no significant effect was observed due to other factors. The P-value (0.016) of T&WS is lower than 0.05 and therefore is significant. The most significant factors were T, MPS and WS. Metering pump speed was observed to have interaction with winding speed; the speeds' relationship oriented the fiber chains as well as added different spin draw ratio, having an effect on drawability later. Multiple and individual regressions optimized for the quality required for various applications and identified the factors' effects and interactions to determine the direction of those that are significant by using the estimated response surfaces. A twist was observed in the 3D surface response diagrams for T and WS (**Table 5**), thus the interaction is significant and agrees with the previous statistical results. This interaction will affect the structure of the as-spun fibers and help to extend the chains to achieve high orientation along the axis of fiber. The regression Eq. (1) was obtained from the analysis and forms the simplified models of the experimental data (coded values in **Table 4**). The regression equations forecast the fiber properties and accurately predict the properties in the final fibers produced. The mathematical regression model forms one of the basic source codes in the designed forecasting application, which will present the extrusion of aromatic-aliphatic co-polyester fiber.

> Drawability a b T c MPS d QA e SF f WS b T MPS b T QA b T SF b T WS b MPS QA b MPS SF b MPS WS b QA SF b QA WS b SF WS = + ∗ +∗ − ∗ −∗ +∗ + ∗∗ + ∗∗ + ∗∗ − ∗∗ −∗ ∗ − ∗ ∗−∗ ∗ −∗ ∗+∗ ∗ − ∗∗ 1 2 34 5 67 8 9 10 (1)

Where: a, b, c, d, e, f b1–10, are statistical constants for the drawability calculated by the **STATGRAPHICS** program.

They were also affected by high extrusion speed at which the shear rate affects the morphological structure [126]. Employing the same technique, the overall orientation, spin draw ratio, crystallographic order, die head pressure, diameter, tensile properties, thermo-graphic measurement and thermal shrinkage were also analyzed and modeled. The statistical analysis models simulated the significant factors, their interactions, and gave useful results with some expected outliers which could be due to experimental and/or testing errors.

### **6.2 Forecasting program for the fiber extrusion**

In the programming process, the relationship between the key inputs (factors) and the performance measures (responses) using factorial statistical experimental design technology are reported. The statistical data and regression formulas are represented as a computer application. Microsoft Visual Basic was used to write a forecasting program that could be utilized for the as-spun AAC fibers' extrusion process. The program offers the management of regression models for responses based on statistical factorial design, design analysis and process simulation. Conversion and summarization of the C++ source code into a simple flow chart was completed (**Figure 5**).

After selecting the polymer grade, the program requests the parameters' values, calculates the values' responses by using regression equations and then gives the results. The data from the input conditions was used to obtain the structural, mechanical and physical data. The program was designed as two windows. The first window is the input window for process conditions (**Figure 6**); the second interface is the output result window (**Figure 7**).

*Characterization, Modeling and the Production Processes of Biopolymers in the Textiles Industry DOI: http://dx.doi.org/10.5772/intechopen.96864*

**Figure 5.** *Schematic program process.*

#### **Figure 6.**

*The main input interface/window for process conditions input.*


#### **Figure 7.**

*The output interface/window for filament temperature in the machine's cooling window and the fiber's structural, mechanical and physical properties.*

Each factor is represented as a record and it may be owned by more than one record, leading to a network-like structure. The multiple regression analysis and previous forecasting models provide a basis for identifying the relationship between process-input and process-output data; and formation of a source code to be used in the forecasting program. The 30 hole spinneret (diameter is 0.4 mm, l/d ratio is 1.2) was used. The programmed application powerfully supports product development, design process control, quality assurance and product performance evaluation; it displays data on the screen or sends data to a file or other devices. **Figure 7** shows the output interface/window for filament temperature in the machine's cooling window and the fiber's structural, mechanical and physical properties. Each factor is represented as a record and relationships between other factors through a matrix design.
